Prevention of Salmonella Enteritidis in 
Shell Eggs During Production, Storage, 
and Transportation (Layers with Access 
to Areas Outside the Poultry House): 
Questions and Answers Regarding the 
Final Rule:   
Guidance for Industry 
 
Additional copies are available from: 
Office of Food Safety 
Division of Dairy, Egg and Meat Products, HFS-315 
Center for Food Safety and Applied Nutrition 
Food and Drug Administration 
5001 Campus Drive 
College Park, MD 20740 
(Tel) 240-402-2385 
 
https://www.fda.gov/FoodGuidances 
 
 
You may submit either electronic or written comments regarding this guidance at any 
time.  Submit electronic comments to https://www.regulations.gov.  Submit written 
comments to the Dockets Management Staff (HFA-305), Food and Drug Administration, 
5630 Fishers Lane, rm. 1061, Rockville, MD 20852.  All comments should be identified 
with the docket number listed in the notice of availability that publishes in the Federal 
Register. 
 
 
U.S. Department of Health and Human Services 
Food and Drug Administration 
Center for Food Safety and Applied Nutrition 
 
August 2022  Contains Nonbinding Recommendations 
 
 
 
 
Table of Contents 
 
 
 
 
 
I.  Introduction ....................................................................................................... 3 
II.  Background ....................................................................................................... 4 
III. Questions and Answers .................................................................................... 6 
A. Coverage of the Egg Rule ................................................................................. 6 
B.  Definitions ........................................................................................................ 6 
C.  SE Prevention Measures .................................................................................. 7 
D.  Environmental Sampling for SE .................................................................... 13 
E.  Other ............................................................................................................... 13 
IV.  References ....................................................................................................... 13 
  2    Contains Nonbinding Recommendations 
 
Prevention of Salmonella Enteritidis 
in Shell Eggs During Production, 
Storage, and Transportation (Layers 
with Access to Areas Outside the 
Poultry House): Questions and 
Answers Regarding the Final Rule: 
Guidance for Industry1
 
 
 
This guidance represents the current thinking of the Food and Drug Administration (FDA or we) 
on this topic.  It does not establish any rights for any person and is not binding on FDA or the 
public.  You can use an alternative approach if the approach satisfies the requirements of the 
applicable statutes and regulations.  To discuss an alternative approach, contact the FDA staff 
responsible for this guidance as listed on the title page.   
 
I.  Introduction 
The purpose of this document is to provide guidance to egg producers on certain provisions 
contained in FDAs July 9, 2009, final rule Prevention of Salmonella Enteritidis in Shell Eggs 
During Production, Storage, and Transportation (74 FR 33030, codified at 21 CFR part 118), that 
reference the poultry house.  Specifically, this document provides guidance to shell egg producers 
whose production systems provide laying hens with access to areas outside of a poultry house as 
that term is defined in 21 CFR 118.3.   
 
The contents of this document do not have the force and effect of law and are not meant to 
bind the public in any way, unless specifically incorporated into a contract.  This document is 
intended only to provide clarity to the public regarding existing requirements under the law.  
FDA guidance documents, including this guidance, should be viewed only as 
recommendations, unless specific regulatory or statutory requirements are cited.  The use of 
the word should in FDA guidances means that something is suggested or recommended, but 
not required. 
 
Under 21 CFR Part 118 (Part 118), which is a regulation that was promulgated by FDA and is 
administered by FDA, certain requirements apply only to the poultry house as that term is 
defined in 21 CFR 118.3.  As discussed above, this document provides guidance to shell egg 
producers regarding compliance with Part 118, specifically in the context of production 
 
1 This guidance has been prepared by the Office of Food Safetys Division of Dairy, Egg and Meat Products in the 
Center for Food Safety and Applied Nutrition at the U.S. Food and Drug Administration. 
  3    Contains Nonbinding Recommendations 
systems that provide laying hens with access to areas outside of a poultry house. As part of 
this guidance, FDA has identified which areas FDA considers to be outside the poultry 
house, as that term is defined in 21 CFR 118.3.  This document does not address the 
requirements of the United States Department of Agriculture (USDA) National Organic 
Program (NOP).  FDA is aware that certified organic egg production systems must comply 
with the relevant legal requirements associated with the NOP, including requirements relating 
to outdoor access.  However, FDA does not play any role in interpreting or enforcing such 
provisions.  Nothing in this document should be read as interpreting any of the NOPs 
requirements.  For example, when FDA interprets 21 CFR 118.3 to mean that a certain type of 
housing style is outside the poultry house for the purposes of Part 118, that interpretation 
does not have any bearing on whether this type of housing style meets the requirements for 
outdoor access under the NOP.  To avoid confusion, FDA has changed the terminology 
used in this guidance from outdoor access to access to areas outside the poultry house.    
 
II.  Background 
FDA issued a final rule (the egg rule) on July 9, 2009, requiring shell egg producers and 
certain other persons to implement measures to prevent Salmonella Enteritidis (SE) from 
contaminating eggs on the farm and from further growth during storage and transportation (21 
CFR part 118).  The egg rule became effective September 8, 2009.  The compliance date for the 
egg rule was July 9, 2010, for producers with 50,000 or more laying hens, and July 9, 2012, for 
producers with fewer than 50,000 but at least 3,000 laying hens.  Producers with fewer than 
3,000 laying hens and those that sell all of their eggs directly to consumers are exempt from the 
egg rule. 
 
The egg rule defines the term poultry house at 21 CFR 118.3.  Several provisions within the 
egg rule use the term poultry house.  However, some shell egg production systems include 
areas that are outside of the poultry house.  In these production systems, laying hens are, at least 
sometimes, allowed to go to areas outside of the poultry house.  
 
Four common housing styles are used for laying hens with access to areas outside of the poultry 
house.  The four common housing styles are described and illustrated below in Figure 1. 
 
Indoor Area with Porch: A porch is adjacent to one side of an indoor area.  The porch is enclosed 
with fence material, such as poultry wire; the porchs roof can be solid or made of wire or 
netting.  The porchs floor is often concrete, but can be dirt or grass.  Access holes connect the 
indoor area to the porch. 
 
Indoor Area with Outdoor Run  Row Style:  Multiple flocks are segregated from one another by 
a series of adjacent structures that are lined up in a row, very similar to how houses at an in-line 
farm are arranged.  Each indoor area connects to at least one (often two) outdoor runs.  The 
outdoor runs are fenced, usually with poultry wire.  The fencing prevents poultry from straying 
beyond the entire structure and from moving between houses.  The outdoor run area may have no 
coverage overhead or it may be covered with netting, and the floors are grass or dirt.  Access 
holes connect the indoor areas to the runs.  Runs may be divided into several sections. 
 
Indoor Area with Outdoor Run  Attached Run Style:  An outdoor run is attached either to the 
end of an indoor area (see Figure 1) or to the side of an indoor area, i.e., where a porch would be 
  4    Contains Nonbinding Recommendations 
located.  The outdoor run is a fenced-in area extending from the indoor area; there may be no 
coverage overhead or it may be covered with netting.  The floor of the outdoor run is dirt or 
grass, and the size of the run can vary greatly.  Access holes connect the outdoor run to the side 
or end of the indoor area, depending on where the run is located. 
 
Pasture Containing an Indoor Area: An indoor area is located within an outdoor fenced pasture. 
The indoor area may be a permanent structure or it may be a moveable structure.  Moveable 
structures may be built on skids, or moveable trailers retrofitted with nest boxes may be used.  
The pasture area may have no coverage overhead or it may be covered with netting, and the size 
of the pasture varies greatly.  If the indoor area is moveable, the housing system usually is 
designed such that the pastures can be rotated, i.e., the fencing surrounding the pasture can be 
moved or relocated to fence a fresh patch of pasture, and the indoor area can be moved to the 
new area with a tractor.  In systems with a permanent indoor structure, access holes connect the 
indoor area to the outdoor pasture.  In systems with a moveable structure, access to the outdoor 
pasture area is through some type of opening in the structure, e.g., an open gate if a retrofitted 
trailer is used. 
 
Figure 1:  Illustration of common housing styles used for laying hens with access to areas outside 
of the poultry house. 
 
 
In the Federal Register of July 24, 2013 (78 FR 44483), FDA made available a draft version of 
this guidance.  In the draft guidance, we proposed to consider porches to be part of the poultry 
house because we considered them to be part of a structure used to house poultry.  However, after 
  5    Contains Nonbinding Recommendations 
considering additional information provided in the response to the draft guidance, we have 
concluded that our initial interpretation did not fully consider how the term structure is used 
within the context of 21 CFR 118.3, particularly with respect to the goal of housing poultry and 
considering factors such as protection from the elements and from predation and control of 
temperature, humidity, and lighting.   
III.  Questions and Answers 
 
A. Coverage of the Egg Rule 
1. Does the egg rule apply to me if the laying hens on my farm have access to areas 
outside of the poultry house?  
 
Yes, assuming you meet the criteria for being subject to the rule.  You are subject to the egg rule 
if you are a shell egg producer with 3,000 or more laying hens at a particular farm that does not 
sell all of your eggs directly to consumers and that produces shell eggs for the table market (21 
CFR 118.1(a)).   
 
2. Has FDA issued other guidance that I should consider with respect to my farm? 
 
Yes.  This guidance provides information specific to egg production systems that provide laying 
hens with access to areas that are outside of a poultry house.  You should also be aware of the 
recommendations in the April 2010 Small Entity Compliance Guide, Prevention of Salmonella 
Enteritidis in Shell Eggs During Production, Transportation, and Storage, the December 2011 
Guidance for Industry: Prevention of Salmonella Enteritidis in Shell Eggs During Production, 
Storage, and Transportation (referred to as the December 2011 Guidance), and the July 2015 
Guidance for Industry: Questions and Answers Regarding the Final Rule, Prevention of 
Salmonella Enteritidis in Shell Eggs During Production, Storage, and Transportation.  
 
B.  Definitions 
1. What is the definition of a poultry house? 
 
The egg rule defines a poultry house as a building, other structure, or separate section within a 
structure used to house poultry.  For structures comprising more than one section containing 
poultry, each section that is separated from the other sections is considered a separate house (21 
CFR 118.3).   
 
2. For the purposes of this guidance document, how is FDA using the phrase area outside the 
poultry house? 
 
For the purpose of this guidance document, FDA is using the phrase area outside the poultry house 
to refer to areas to which laying hens have access, but that are not part of the poultry house as that 
term is defined in 21 CFR 118.3.  For example, such areas include porches, outdoor runs, and pastures 
to which laying hens have access.  In the context of this guidance document, the phrase area outside 
the poultry house does not refer to any parts of your farm to which your laying hens do not have 
access.   
  6    Contains Nonbinding Recommendations 
 
3. Is a porch for layers considered part of a poultry house? 
 
No.  FDA does not consider a porch, as described in section II, to be within the definition of a 
poultry house.  A porch consists of an area enclosed with fence material; a roof or other covering 
(solid or made of wire or netting); and a floor of concrete, dirt, or grass.  Hens use access holes to 
move between the poultry house and the porch.  Unlike the poultry house, the porch does not 
provide substantial protection from the elements or predation, nor does it allow for control of 
temperature, humidity, and lighting.  FDA does not consider the porch to be a building, structure, 
or part of a structure used to house poultry, and it therefore does not consider the porch to be part 
of a poultry house. 
 
4. Is an outdoor run considered part of a poultry house?  
 
No.  FDA does not consider an outdoor run to be within the definition of a poultry house.  
Row-style and attached run-style housing consists of a fenced-in outdoor area adjacent to a 
poultry house.  The outdoor run area may have no coverage overhead or it may be covered 
with netting, and the floors are grass or dirt.  Hens use access holes to move between the 
poultry house and the outdoor run.  Unlike the poultry house, the outdoor run does not 
provide substantial protection from the elements or predation, nor does it allow for control 
of temperature, humidity, and lighting.  FDA does not consider the outdoor run to be a 
building, structure, or part of a structure used to house poultry, and it therefore does not 
consider the outdoor run to be part of a poultry house. 
 
5. Is a pasture surrounding an indoor area considered part of a poultry house? 
 
No.  FDA does not consider pastured areas to be part of a poultry house.  Pastured housing consists 
of a poultry house (either permanent or moveable) located within a fenced-in pasture.  FDA does 
not consider the pasture to be a building, structure, or part of a structure used to house poultry, and 
it therefore does not consider the pasture to be part of a poultry house. 
 
6. For other styles, how will FDA determine whether an area outside of a poultry house 
is part of a poultry house? 
 
The analysis of whether an area is part of a poultry house begins with the definition of poultry 
house in 21 CFR 118.3.  (See question III.B.1.)  To determine whether or not an area fits into this 
definition, FDA will consider factors such as the extent to which the area provides protection from 
the elements and from predation and allows control of temperature, humidity, and lighting, and 
therefore provides an environment that is conducive to egg production.    
 
C.  SE Prevention Measures 
1. Must I prevent stray poultry, wild birds, cats, and other animals from entering the 
poultry house? 
 
Yes.  You must prevent stray poultry, wild birds, cats, and other animals from entering poultry 
houses (21 CFR 118.4(b)(4)).   
 
 
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2. Should I prevent stray poultry, wild birds, cats, and other animals from entering an 
area outside the poultry house? 
 
You must take steps to ensure that there is no introduction or transfer of SE into or among poultry 
houses (21 CFR 118.4(b)).  Wild birds are common vectors of SE (Andres-Barranco et al., 2014; 
Awadallah et al., 2013; Cizek et al., 1994; Craven et al., 2000; Davies and Breslin, 2003; Lawson 
et al., 2014; Liebana et al., 2003; Macdonald and Brown, 1974; Mancini et al., 2014; 
Obukhovaska, 2013; Tizard, 2004; Troxler, 2009).2  Cats and other animals also can be vectors of 
SE (Dewaele et al., 2012). 
 
When there is movement of hens between the poultry house and an area outside the poultry 
house, this movement can lead to the transfer of SE between the two areas.  In this situation, to 
ensure that there is no introduction or transfer of SE into the poultry house, you should take 
appropriate steps to prevent stray poultry, wild birds, cats, and other animals from entering the 
area outside the poultry house. 
 
3. How can I prevent stray poultry, wild birds, cats and other animals from entering an area 
outside the poultry house? 
 
Examples of steps you can take to prevent stray poultry, wild birds, cats and other animals from 
entering an area outside the poultry house include limiting layers access to areas outside the 
poultry house to hours when wild birds or other animals are not likely to be present, maintaining 
attractions, such as feed and water, in areas where they do not attract these animals, and 
temporarily confining layers during periods of wild fowl migration.  In some cases, additional 
steps may be needed to control stray animals in the area outside of the poultry house. 
 
The presence of stray poultry, wild birds, cats or other animals in an area outside the poultry house 
indicates that this route of exposure of the flock to SE is not adequately controlled.  Therefore, 
FDA recommends that the presence of these animals within an area outside the poultry house 
should prompt implementation of further facility-specific biosecurity steps, such as those described 
above, in addition to any steps of this type that your farm already has in place.  
 
4. Must I monitor for rodents and flies and, when monitoring indicates unacceptable rodent 
or fly activity within a poultry house, use appropriate methods to achieve satisfactory rodent 
and fly control? 
 
Yes.  You must monitor for rodents by visual inspection and mechanical traps, glueboards, or 
another appropriate monitoring method and, when monitoring indicates unacceptable rodent 
activity within a poultry house, use appropriate methods to achieve satisfactory rodent control (21 
CFR 118.4(c)(1)).  Similarly, you must monitor for flies by spot cards, Scudder grills,3 sticky 
 
2  FDA promulgated the egg rule to prevent SE from contaminating eggs.  However, we note that some of the 
requirements of the egg rule also can help prevent the spread of other diseases.  For example, wild birds can be a 
vector for Highly Pathogenic Avian Influenza (HPAI).  Many of the same steps that can prevent the introduction of SE 
into a flock can also help prevent the introduction of HPAI and other diseases. 
3 A Scudder grill consists of 16 to 24 wooden slats, fastened at equal intervals to cover an area of approximately 0.8 
square meters. The grill is placed where there are natural fly concentrations and the number of flies landing on the grill 
 
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traps, or another appropriate monitoring method and, when monitoring indicates unacceptable fly 
activity within a poultry house, use appropriate methods to achieve satisfactory fly control (21 
CFR 118.4(c)(2)).   
 
5. Should I monitor for rodents and flies in an area outside the poultry house and, when 
monitoring indicates unacceptable rodent or fly activity in that area, use appropriate 
methods to achieve satisfactory rodent and fly control? 
 
As discussed in the answer to question C.2., you must take steps to ensure that there is no 
introduction or transfer of SE into or among poultry houses (21 CFR 118.4(b)).  Rodents and flies 
are known vectors of SE (Olsen and Hammack, 2000; Meerburg and Kijlstra, 2007).  When there 
is movement of hens between the poultry house and an area outside the poultry house, this 
movement can lead to the transfer of SE between the two areas.  In this situation, to ensure that 
there is no introduction or transfer of SE into the poultry house, you should take appropriate steps 
to monitor for and control rodents and flies in the area outside the poultry house.  Integrated 
management of rodents and flies includes a multilevel approach (prevention, monitoring, and 
control) to ensure the effectiveness of the pest control program. 
 
Unacceptable fly and rodent activity can occur in areas outside the poultry house for a variety of 
reasons.  For example, excessive flies in and around laying hens that are outside the poultry 
house can be caused by, among other things, excessive manure in areas of entry to portable 
housing units, excessive manure near feeding areas, or dead animals that have not yet been 
removed.  Excessive rodent activity can be caused by some of the same factors or can be caused 
by other circumstances.  For example, when laying hens have access to a river or pond, producers 
might find that they need to take steps to control the rodent population at and near that water 
source, since rivers and ponds can attract rodents.  In any situation where monitoring indicates 
unacceptable fly or rodent activity in an area outside the poultry house, producers should use 
appropriate methods to achieve satisfactory fly or rodent control to prevent SE from being 
introduced into the poultry house.  
 
6. How can I prevent rodents from entering an area outside the poultry house? 
 
Native field rodents, such as voles, are adapted to live in natural habitats.  In areas outside the 
poultry house it is impossible to exclude rodents in the same way as within the poultry house, but it 
is possible to reduce their numbers to minimize the possibility of contact with laying hens 
(Meerburg et al., 2004).  One important component of a rodent management program is to adopt a 
preventive approach, using a variety of strategies (DEFRA, 2001).  While recognizing that 
exclusion of all rodents from an area outside the poultry house might not be possible, FDA 
recommends the following actions to prevent rodents from entering the area: 
 
  Maintaining a 6-foot-wide area around the outside periphery of the area that is filled 
with either gravel or other non-grass substance or, if this is not feasible, maintaining the 
grass within this zone to a short height (maximum of 6 inches).  This would not include 
the removal of trees or shrubs that do not provide harborage for rodents. 
  Removing piles of old material, stacks of straw or hay, trash, weeds, debris, vegetation, 
and any other material, both inside and immediately outside the area, since these can 
 
in a given period of time (usually 30 seconds or l minute) is counted. In each locality, counts are made on 3 to 5 or 
more of the highest fly concentrations found and the results averaged. 
 
  9    Contains Nonbinding Recommendations 
provide harborage for rodents. 
  Removing any dead carcasses daily and disposing of them properly. 
  Minimizing spillage of feed and removing remnants of feed if feeding sites are located 
in areas outside the poultry house. 
  Minimizing access by rodents to feed and water stations. 
 
7. How can I monitor for rodents in an area outside the poultry house? 
 
Rodents are usually present in fields, but in low numbers, since they are confined to refuge areas 
where they are not easily detected (Stratford, 2012).  Because of the potential for rodent activity in 
areas outside the poultry house, FDA recommends monitoring for rodents in these areas as 
described below.  Observation of any of the following is likely to indicate unacceptable rodent 
activity: live rodents, excessive dead rodents, rodent feces (especially in feed or grass), gnaw holes, 
baited traps without bait, nests in traps, presence of native field rodent colonies (such as voles or 
deer mice), surface runways in the grass leading to underground entrance holes, or characteristic 
grass clippings on the floor of runways.  Additional knowledge of the rodent species is helpful, as 
the behavior and preferred habitat of each species can differ, and preventive and control measures 
may need to vary accordingly. 
 
For areas outside the poultry house, FDA recommends monitoring measures such as the use of 
chew cards, also known as bait cards.  These cards are 10 cm x 10 cm paper squares, divided 
into 1-cm2 cells, and soaked in canola oil.  Cards are placed overnight at 10 m intervals across 
the area outside the poultry house to observe the level of feeding damage.  If five percent or 
more of the card is eaten, this indicates moderate rodent activity (Whisson et al., 2005; Stratford, 
2012).  Emphasis should be placed on monitoring feeding and watering stations as well as 
shaded roosting areas. 
 
The following levels are likely to indicate satisfactory rodent control as appropriate: 
 
  Rodent Index (RI): A RI of 1 or less as described in the December 2011 Guidance 
  Chew card (bait cards): An eaten area less than 5 percent 
  Visual inspection: No unacceptable rodent activity during visual inspections, as described 
in the first paragraph of this response 
 
8.  How can I control rodents in an area outside the poultry house? 
 
When monitoring indicates unacceptable rodent activity, effective rodent control measures should 
be applied.  Control measures can include both mechanical and physical methods.   
 
For areas outside the poultry house, FDA recommends that you use a triple line of defense to 
control rodents.  For example: 
 
An effective first line of defense to control rodents would be to place baiting stations/traps at least 
six (6) feet beyond the perimeter fencing surrounding the area outside of the poultry house where 
hens have access and approximately 30-45 feet apart.  The goal is to control the rodents before 
they approach the area outside the poultry house where hens have access. 
 
An effective second line of defense would be to place baiting stations/traps approximately every 
10-15 feet along the outside of the perimeter fence surrounding the area outside of the poultry 
  10    Contains Nonbinding Recommendations 
house where hens have access.  The goal is to control the rodents from entering the area and 
minimize contacts between rodents and hens. 
 
An effective third line of defense would be to place baiting stations/traps approximately every 
eight (8) feet along the outside of the exterior wall of the poultry house and scattered in the area 
outside of the poultry house where hens have access.  The goal is to control the rodents that have 
eluded the previous 2 lines of defenses.  These baiting stations/traps would be protected by 
caging or fencing made of mesh that allows rodents to enter but prevents the hens interfering with 
them. 
 
The baiting stations or other control measures should be checked regularly (we recommend at 
least once a week) and, if necessary, the number of baiting stations/traps should be increased and 
fresh bait added as often as needed. 
 
9. How can I prevent flies in an area outside the poultry house? 
 
Preventive measures to keep fly populations at a minimum are based on cleaning and removing 
areas that support fly larval development.  FDA recommends the following options to prevent 
excessive fly populations in the area outside the poultry house: 
 
  Decreasing the amount of fresh manure. 
  Removing any dead carcasses daily and disposing of them properly. 
  Minimizing accumulations of spilled feed and broken eggs. 
  Keeping grass and weeds mowed to eliminate resting areas for adult flies and to allow for 
adequate air movement. 
  Removing dead or decaying plants (Williams, 2010; Stafford, 2008). 
 
10. How can I monitor for flies in an area outside the poultry house? 
 
Indoor and outdoor fly populations are seasonal and vary year-to-year.  Outdoor fly populations 
usually increase during spring and summer months; indoor fly populations usually increase during 
fall and winter months (Albarrak, 2009; Rutz, 2000).   
 
For areas outside the poultry house, FDA recommends the same monitoring methods 
recommended for poultry houses, such as spot cards, fixed sticky tape, moving sticky tape, 
Scudder grills, or baited traps.  These methods are described in Section III.A.2 in the December 
2011 Guidance.  Monitoring devices should be placed on stakes off the ground or hung from 
poles strategically placed throughout the area outside of the poultry house.  Some of the baits or 
fly attractants used in these products can be affected by sunlight; thus, to the extent possible, the 
device chosen should be placed under some type of cover, e.g., a plywood or tin metal square of 
sufficient size to keep the monitoring device out of direct sunlight. 
 
The following levels are likely to indicate satisfactory fly control as appropriate: 
 
  Spot Card Method: A spot card index of 50 or fewer per card 
  Fixed Sticky Tape Method: A weekly count of 50 or fewer flies per tape 
  Moving Sticky Tape Method: A count of 75 or fewer flies per tape 
  Scudder Grill: A count of less than 20 on a Scudder grill (see footnote 2) 
  11    Contains Nonbinding Recommendations 
  Baited Traps:  A fly count of 250 or fewer flies per week. 
 
11. How can I control for flies in an area outside the poultry house? 
 
When monitoring indicates unacceptable fly activity, effective fly control measures should be 
applied.  FDA recommends that you control for flies in the area outside the poultry house in a 
manner similar to that used within the poultry house, including sticky traps and/or baited traps.   
 
For areas outside the poultry house, FDA recommends control measures that include mechanical 
and physical methods.  Products designed for outdoor use are available for use with the methods 
requiring some type of bait or fly attractant.  Also, you should identify fly breeding sites and alter 
or eliminate the source that seems to attract the flies and/or allow them to breed.  Insecticides 
should not be used as a substitute for good management and sanitation.  If using insecticides, only 
those products that are approved for poultry farm use should be considered, and these should be 
carefully applied following directions for use (Berry, 2009).  The chickens themselves should not 
be considered a control mechanism for flies since flies can carry SE (Olsen and Hammack, 2000).  
Although darkling beetles (Alphitobius diaperinus) and hister beetles (Carcinops pumilio) are 
predators of flies, their use to control fly populations is not recommended because they are vectors 
of SE (Despins et al., 1988; Gray et al., 1999; Skov et al., 2004; Roche et al., 2009).  Other 
biological control agents have been proposed to control flies.  However, at this time it is unknown 
if any of the other proposed biological controls can serve as vectors of SE, so care should be taken 
when using them. 
 
12. Must I remove vegetation and debris that may provide harborage for pests in the 
area outside the poultry house? 
 
Yes.  You must remove debris within a poultry house and vegetation and debris outside a poultry 
house that may provide harborage for pests (21 CFR 118.4(c)(3)). 
 
13. How should I maintain my vegetation in the area outside the poultry house so that 
it does not provide harborage for pests? 
 
If the area outside the poultry house contains vegetation that poses a potential harborage for 
rodents, FDA recommends that it be kept at a short height (6 inches or less) to ensure it does not 
provide harborage for rodents.  Because most trees do not pose a potential harborage for rodents or 
other pests, it is generally not necessary to remove trees in order to comply with 21 CFR 
118.4(c)(3).  In production systems where birds are rotated through pastures, the 6-inch height 
recommendation only applies to pastures that contain birds. 
 
14. Must I clean and disinfect the area outside the poultry house prior to adding new laying 
hens if I have had one or more SE positive test results (environmental or egg)? 
 
You must clean and disinfect the poultry house before new laying hens are added to the house, if 
you have had an environmental test or an egg test that was positive for SE at any point during the 
life of a flock that was housed in the poultry house prior to depopulation (21 CFR 118.4(d)). 
 
This requirement does not apply to areas outside the poultry house.  However, as is discussed in 
the answer to question C.2., you must take steps to ensure that there is no introduction or transfer 
of SE into or among poultry houses (21 CFR 118.4(b)).  In a situation where a poultry house is 
  12    Contains Nonbinding Recommendations 
being repopulated following an SE-positive environmental test or egg test, FDA recommends that 
you take steps to eliminate SE from areas outside the poultry house before adding new laying 
hens. 
 
15. How can I clean and disinfect an area outside the poultry house? 
 
For areas outside the poultry house with concrete or wood floors, FDA recommends cleaning and 
disinfecting these areas in the same manner FDA recommends for the poultry house.  Please refer 
to Section III.A.3 in the December 2011 Guidance.  If the ground is dirt or grass, tilling the soil 
may be part of an effective strategy to remove visible manure and potentially-contaminated dust, 
feathers, and old feed.  In some situations, it might make sense to rotate the area outside the poultry 
house to which laying hens have access, so that the area that was in use at the time of the SE-
positive test result is no longer in use.  Allowing the potentially-contaminated area to lie dormant 
between flocks could be part of an effective disinfection strategy.  If an area is left dormant in this 
manner, appropriate biosecurity measures should be put in place to ensure that SE is not transferred 
out of the dormant area via employees or equipment. 
 
D.  Environmental Sampling for SE 
1. Must I sample an area outside the poultry house for SE? 
 
No.  While you must sample the poultry house environment using a sampling plan appropriate to 
the poultry house layout (21 CFR 118.7(a)), this requirement does not apply to areas outside the 
poultry house. 
 
E.  Other 
1.  If I vaccinate my hens that have access to the area outside the poultry house, am I still 
required to follow all of the SE prevention measures in the egg rule? 
 
Yes.  FDA concluded in the egg rule (74 FR 33030 at 33035) that data on the efficacy of vaccines 
are not sufficient to allow substitution of vaccination for any of the SE prevention measures.  
Therefore, the rule does not exempt a producer who vaccinates its birds from the SE prevention 
measures that are required by the rule.  Vaccination against SE is most effective when it is one part 
of a larger SE prevention plan which includes SE-monitored pullets, effective biosecurity 
measures, effective rodent and fly control, thorough cleaning and disinfection procedures, and a 
monitoring program for SE in the environment and eggs.  If you have identified a vaccination 
program that is effective for your particular farms, FDA encourages the use of this program as an 
additional SE prevention measure. 
 
IV.   References 
The following references marked with an asterisk (*) are on display at the Dockets Management 
Staff, (HFA-305), Food and Drug Administration, 5630 Fishers Lane, Rm. 1061, Rockville, MD 
20852, and are available for viewing by interested persons between 9 a.m. and 4 p.m., Monday 
through Friday; they are also available electronically at https://www.regulations.gov.  References 
without asterisks are not on public display at https://www.regulations.gov because they have 
copyright restriction.  Some may be available at the website address, if listed.  References without 
asterisks are available for viewing only at the Dockets Management Staff.  FDA has verified the 
  13    Contains Nonbinding Recommendations 
website addresses, as of the date this document publishes in the Federal Register, but websites are 
subject to change over time. 
 
1.  Albarrak, A. S. Comparative studies on housefly, Musca domestica L., population in 
different animal farms in relation to attractants and control at Hail Province, Saudi Arabia. 
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2.  Andres-Barranco, S., J. P. Vico, V. Garrido, S. Samper, S. Herrera-Leon, C. de Frutos and R. 
C. Mainar-Jaime. Role of wild birds and rodents in the epidemiology of subclinical 
salmonellosis in finishing pigs. Foodborne Pathog. Dis. 11(9):689-697. 2014. 
 
3.  Arzey, G., E. Macarthur and I. Littleton. NSW biosecurity guidelines for free range poultry 
farms. 2007. 
 
4.  Awadallah, M. A., A. M. Merwad and R. E. Mohamed R. E. Prevalence of zoonotic E 
scherichia coli and Salmonellae in wild birds and humans in Egypt with emphasis on RAPD-
PCR fingerprinting of E. coli. Glob. Vet. 11(6):781-788. 2013. 
 
5.  Berry, J. G. Fly control in the poultry house, ANSI-8206. Oklahoma Cooperative Extension 
Service, Oklahoma State University. 2009. Available at:  
https://shareok.org/bitstream/handle/11244/49949/oksd_ansi_8206_2003-
08.pdf?sequence=1&isAllowed=y.* 
 
6.  Cizek, A., I. Literak, K. Hejlicek, F. Treml and J. Smola. Salmonella contamination of the 
environment and its incidence in wild birds.  Zantralbl. Veterinarmed. B. 41:320-327. 1994. 
 
7.  Cox, B. BC Poultry Biosecurity Reference Guide. BC Poultry Association, Canada. 2006. 
Available at: http://bcchicken.ca/wp-
content/uploads/2012/11/FullCopyUpdatedJan2012.pdf.* 
 
8.  Cozens, M. Salmonella enteritidis monitoring and certification program, Queensland. 2010. 
Available at:  
https://www.daf.qld.gov.au/__data/assets/pdf_file/0010/73198/Salmonella-enteritidis-
program.pdf.* 
 
9.  Craven, S., N. J. Stern, E. Line, J. S. Bailey, N. A. Cox and P. Fedorka-Cray. Determination 
of the incidence of Salmonella spp., Campylobacter jejuni, and Clostridium perfringens in 
wild birds near broiler chicken houses by sampling intestinal droppings. Avian Dis. 44:715-
720. 2000.* 
 
10. Davies, R. H. and M. Breslin. Observations on Salmonella contamination of commercial 
laying farms before and after cleaning and disinfection. Vet. Rec. 152:283-287. 2003. 
 
11. Department for Environment, Food and Rural Affairs. The welfare of hens in free range 
systems. London, U.K. 2001. Available at: https://secure-
web.cisco.com/1waaNxk6luujOeFRPQlTFov3_lTxj760h7xiLDH2kT6qzahyYF-
ueLzTX6yuXdvNseBA19TbuD2gjRZk8OSBlExxsubUTJPxF6x3sUCFs-
Sun6kVi9rfvlaC67Ls4SAnhlnOpkiKA8AuGyRpR8PbNerP6MREPCas5uHUdWUqLaPR6H
j1rW8gqO6RsBYMV-
  14    Contains Nonbinding Recommendations 
ynGtlUfqAQwveorzEZUL2j23mPwUPegMvWFsRiMvOV6ZDs/https%3A%2F%2Fassets.p
ublishing.service.gov.uk%2Fgovernment%2Fuploads%2Fsystem%2Fuploads%2Fattachmen
t_data%2Ffile%2F69366%2Fpb6490-hens-020130.pdf. 
 
12. Despins, J. L., J. A. Vaughan and E. C. Turner. Role of the lesser mealworm, Alphitobius 
diaperinus (Panzer) (Coleoptera: Tenebrionidae), as a predator of the house fly, Musca 
domestica L. (Diptera: Muscidae), in poultry houses. Coleopt. Bull. 42(3):211-216. 1988.* 
 
13. Dewaele, I., G. Rasschaert, C. Wildemauwe, H. Van Meirhaeghe, M. Vanrobaeys, E. De 
Graef, L. Herman, R. Ducatelle, M. Heyndrickx and K. De Reu. Polyphasic characterization 
of Salmonella Enteritidis isolates on persistently contaminated layer farms during the 
implementation of a national control program with obligatory vaccination: A longitudinal 
study. Poult. Sci. 91:27272735. 2012. 
 
14. Dewaele, I., H. Van Meirhaeghe, G. Rasschaert, M. Vanrobaeys, E. De Graef, L. Herman, R. 
Ducatelle, M. Heyndrickx and K. De Reu. Persistent Salmonella Enteritidis environmental 
contamination on layer farms in the context of an implemented national control program 
with obligatory vaccination. Poult. Sci. 91:282291. 2012. 
 
15. Geden, C. J. Methods for monitoring outdoor populations of house flies, Musca domestica L. 
(Diptera: muscidae).  J. Vector Ecol. 30(2):244-250. 2005.* 
 
16. Gray, J. P., C. W. Maddox, P. C. Tobin, J. D. Gummo and C. W. Pitts. Reservoir 
competence of Carcinops pumilio for Salmonella enteritidis (Eubacteriales: 
Enterobacteriaceae). J. Med. Entomol. 36(6):888-891. 1999. 
 
17. Kuney, D. R. Poultry fact sheet  Guidelines for risk reduction of microbial introduction into 
poultry flocks and products. University of California Cooperative Extension. 1999.* 
   
18. Lawson, B., E. de Pinna, R. A. Horton, S. K. Macgregor, S. K. John, J. Chantrey, J. P. Duff, 
J. K. Kirkwood, V. R. Simpson, R. A. Robinson, J. Wain and A. A. Cunningham.  
Epidemiological evidence that garden birds are a source of human salmonellosis in England 
and Wales. PLOS ONE. 9(2):e88968. 2014. 
 
19. Liebana, E., L. Garcia-Migura, C. Clouting, F. A. Clifton-Hadley, M. Breslin and R. H. 
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maintenance of Salmonella Enteritidis infection in layer farms. J. Appl. Microbiol. 94: 1024-
1029. 2003. 
 
20. MacDonald, J. W. and D. D. Brown. Salmonella infection in wild birds in Britain. Vet. Rec. 
94(14):321-322. 1974.* 
 
21. Mancini, L., S. Marcheggiani, A. DAngelo, C. Puccinelli, F. Chiudioni, F. Rossi, E. 
Delibato, D. De Medici, A. M. Dionisi, S. Owczarek and I. Luzzi. First isolation of 
Salmonella enterica serovar Napoli from wild birds in Italy. Ann 1st Super Sanita. 50(1):96-
98. 2014.* 
 
22. Meerburg, B. G., M. Bonde, F. W. A. Brom, S. Endepols, A. N. Jensen, H. Leirs, J. Lodal, 
  15    Contains Nonbinding Recommendations 
G. R. Singleton, H. J. Pelz, T. B. Rodenburg and A. Kijlstra. Towards sustainable 
management of rodents in organic animal husbandry. Njas-Wagen. J. Life Sc. 52:195-205. 
2004.* 
 
23. Meerburg, B. G. and A. Kijlstra. Role of rodents in transmission of Salmonella and 
Campylobacter. J. Sci. Food Agric. 87:27742781. 2007. 
 
24. Obukhovaska, O. The national reservoirs of Salmonella Enteritidis in populations of wild 
birds. ISDS 2012 Conference Abstracts. Online J. Public Health Inform. 5(1):e171. 2013.* 
 
25. OIE Terrestrial Animal Health Standards Commission. Terrestrial animal health code, 
chapter 6.4: biosecurity procedures in poultry production. World Organization for Animal 
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26. Olsen, A. R. and T. S. Hammack. Isolation of Salmonella spp. from the housefly, Musca 
domestica L., and the dump fly, Hydrotaea aenescens (Wiedemann) (Diptera: Muscidae), at 
caged-layer houses. J. Food Prot. 63:958-960. 2000.* 
 
27. Roche, A. J., N. A. Cox, L. J. Richardson, R. J. Buhr, J. A. Cason, B. D. Fairchild and N. C. 
Hinkle. Transmission of Salmonella to broilers by contaminated larval and adult lesser 
mealworms, Alphitobius diaperinus (Coleoptera: Tenebrionidae). Poult. Sci. 88:44-48. 2009. 
 
28. Rutz, D. A. Pest management recommendations for poultry. College of Agricultural 
Sciences, Pennsylvania State University. 2000. Available at: 
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29. Skov, M. N., A. G. Spencer, B. Hald, L. Petersen, B. Nauerby, B. Carstensen and M. 
Madsen. The role of litter beetles as potential reservoir for Salmonella enterica and 
thermophilic Campylobacter spp. between broiler flocks. Avian Dis. 48:9-18. 2004. 
 
30. Stafford, K. C. III. Integrated fly management in poultry operations. Fly management 
handbook, a guide to biology, dispersal, and management of the housefly and related flies for 
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/media/CAES/DOCUMENTS/Publications/Bulletins/b1013pdf.pdf. 
 
31. Stratford, G. Mice. Agriculture Victoria, Victoria, Australia. Note number AG1414. 2012.  
 
32. Tizard, I. Salmonellosis in wild birds. Semin. Avian Exot. Pet Med. 13(2):50-66. 2004. 
 
33. Troxler, S. Fact sheet: frequently asked questions regarding the wild birds unlimited seed 
recall and salmonellosis in wild birds in North Carolina. NC Department of Agriculture and 
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34. United States Department of Agriculture/Animal and Plant Health Inspection Service.  
Further guidance on biosecurity and disease prevention and control for nonconfinement 
poultry production operations.  USDA/APHIS/Veterinary Services. 2005.* 
 
  16    Contains Nonbinding Recommendations 
35. Whisson, D. A., R. M. Engeman and K. Collins. Developing relative abundance techniques 
(RATs) for monitoring rodent populations. Wildl. Res. 32:239-244. 2005. 
 
36. Williams, R. Livestock and poultry, control of poultry pests, E-3-W. Purdue University, 
Department of Entomology. 2010. Available at: 
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  17