Method for the microaerosol fumigation of newly hatched poultry

A method of fumigation which will destroy microorganisms in the environment of hatching and newly hatched poultry whereby a disinfecting solution such as hydrogen peroxide is applied into the environment by a microaerosol. The method significantly reduces the level of microorganisms in the environment and reduces the risk of post hatch transfer of potentially disease causing microorganisms, without adversely affecting the viability of the newly hatched poultry.

BACKGROUND OF THE INVENTION 
The present invention relates to a method for reducing microorganisms in 
the environment of newly hatched poultry which reduces the chance of 
transmission of disease in the hatchery. 
The environment of newly hatched poultry quickly becomes contaminated with 
microorganisms as soon as the actual hatching process or exit from the 
eggs begins. The microorganisms include, but are not limited to, (1) 
bacteria such as Salmonella species, Escherichia coli, staphylococcus 
aureus and (2) fungal organisms such as members of fungal genus 
Aspergillus, and possibly avian Mycoplasmas. This rapid rise in the 
concentration of microorganisms is often referred to as a bacterial bloom 
which follows the pipping stage of incubation in poultry. It is at his 
stage that optimum conditions for growth of microorganisms exists in terms 
of humidity, temperature, and nutrient levels. Organic debris present from 
the hatching process provides abundant levels of nutrients enhancing 
microbial replication at this time. 
The microbial levels in this environment are commonly measured by 
microbiological culture of air or by measurement of microbial levels 
contained on specific quantities of hatcher down or fluff (a by product of 
the bird produced during hatch). 
The method required by government regulation for at least the last 40 years 
to reduce this environmental contamination is to generate formaldehyde gas 
by either physically mixing formalin with potassium permanganate, or more 
conveniently by evaporating formalin on a continuous basis during the last 
few days of the hatching process. While the use of formaldehyde does 
reduce the level of microorganisms in the environment it is becoming more 
difficult to use due to the public health concerns about exposure of 
humans to this compound. 
Another significant concern with the use of formaldehyde in the post 
pipping stage of hatching is the adverse effect of this compound of the 
physical integrity of the avian respiratory system. Published literature 
documents this affect. The physical damage caused to the avian respiratory 
system by formaldehyde may predispose the animals to increased 
susceptibility to respiratory disease encountered in the early days of 
life. 
It will be understood that while the invention has application to the 
environment of avian chicks after they are hatched and that the method in 
accordance will affect the portion of chicks that survive. Thus, one 
effect of the use of the method in accordance is to improve the 
hatchability of eggs since that term is defined as the portion of chicks 
that survive the hatching process. 
The incubation process in commercially raised-avian species such as 
chickens and turkeys is conventionally carried out initially in setters 
and then in a type of incubator referred to as a hatcher. In the hatcher 
the respiratory system of the embryo converts to a direct air breathing 
animal (the pipping stage), as opposed to air exchange across the egg 
shell. The control of temperature and humidity are especially critical at 
this point of hatching. Levels of moisture too high or too low will 
interfere with the hatching process and result in decreased hatch 
percentage and or inferior post hatch performance of hatched poultry. 
It is because of this that a gaseous disinfectant such as formaldehyde is 
desirable because it can be administered continuously from the point of 
pipping when the microorganism bloom occurs up until essentially all the 
poultry have exited from the egg without significantly increasing the 
moisture level in the environment. The time for this to happen may be up 
to thirty hours which precludes conventional methods of disinfectant 
application such as spraying, conventional automatic foggers or even 
continuous administration through the hatcher humidifying system. All of 
these methods would produce humidity levels too high when used on a 
continuous basis resulting in a smaller percentage of chicks surviving the 
hatching process or poor post hatch performance. 
The prior art includes U.S. Pat. No. 4,932,359 which discloses a process 
for sanitizing eggs by exposing the eggs to a solution of hydrogen 
peroxide during one or more stages of the hatchery process. The teachings 
of that patent are expressly limited to application until the actual time 
of pipping and hatching. Thus, there is no teaching of application after 
pipping. It is an object of the invention to have a method which will 
provide continuous protection for commercially raised poultry from the 
time the birds first break through the egg shell until they are removed 
from the hatchery environment. 
It is still another object of the invention to provide such a method to 
decrease environmental microbial contamination without adversely affecting 
the proportion of birds that survive the hatching process. 
It is another object of the invention to provide a method to accomplish the 
above which would not adversely affect the post hatch performance of the 
poultry. 
SUMMARY OF THE INVENTION 
It has now been found that these and other objects of the invention may be 
attained in a method in which a disinfectant solution is administered into 
the environment of newly hatched poultry after the point the birds break 
through the eggshell up until the time they are removed from the hatchery 
environment. The method permits a disinfectant solution to be administered 
continuously during this time period without adversely affecting the 
proportion of chicks that survive the hatching process or subsequent post 
hatch performance. 
In one form of the invention a microaerosol dispensing apparatus is 
utilized to disperse the disinfectant solution. Ordinarily the 
microaerosol apparatus will provide a particle size in the range of 1 to 
100 microns. The microaerosol dispensing apparatus may be of various 
constructions including but not limited to specialized pneumatic driven 
nozzles, thermal foggers, high velocity airstreams with a venturi nozzle 
or ultrasonic apparatus. Such apparatus is known that will deliver 
solutions in the particle range referred to above. This type of 
application allows for continuous application of disinfectant solutions 
over an extended time period without adversely affecting the portion of 
chicks that survive the hatching process or post hatch performance of 
poultry due to excessive levels of moisture in the environment. 
In some forms of the invention the disinfectant administered is hydrogen 
peroxide or glutaraldehyde or any other disinfectant which is (1) an 
effective antimicrobial agent, (2) minimizes the degree of physical damage 
to the avian respiratory tissue, (3) improves upon or does not decrease 
the percentage of chicks that survive the hatching process, (4) does not 
result in poor post hatch performance, and (5) is safe for people to work 
in the presence of the material. 
While the invention has particular advantages when used in the hatchery 
environment it will be understood that it also has application to other 
closed environments in which the chicks are placed after being hatched. 
For example, the chicks may be placed in a closed truck and the 
microaerosol application may be administered inside the truck while the 
chicks are being transported. The closed environment is particularly 
advantageous because human beings will not be exposed to the disinfectant 
and the chicks will be enveloped by the disinfectant. Thus the invention 
contemplates microaerosol application of a disinfectant to newly hatched 
chicks in the hatcher, in the truck transporting the chicks, both the 
hatcher and the truck or any other closed chamber in which the chicks are 
placed. 
DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Fumigation is widely used in the poultry industry as a method of 
disinfecting surfaces and environments and is normally synonymous with 
formaldehyde fumigation in meaning, in this industry. A major use of this 
method of fumigation has commonly been during the final stage of 
incubation in a hatcher to reduce the microbial contamination in this 
environment. Fumigation by definition is to expose to fumes or volatile 
compounds. Typically this process depends upon vaporization by 
evaporation, or by a chemical reaction to generate a gas. With 
formaldehyde fumigation in the hatcher environment, formaldehyde gas is 
generated by evaporating a formalin solution or by a chemical reaction of 
mixing potassium permanganate with formalin. This gas then saturates the 
environment mixing with the humidity to form formalin on a microscopic 
level to produce the active disinfectant action of this process. 
Formaldehyde has been the method of choice for this application due to its 
effectiveness and ease of use, however the adverse properties of this 
product are restricting its future use. 
The following discussion including examples will demonstrate how the 
present invention is new and unique in that it utilizes microaerosol 
technology to disperse disinfecting solutions into the environment of 
hatching and newly hatched avian species, and will replace formaldehyde 
fumigation typically used in the poultry industry. 
The term microaerosol is used to describe the particle size of a solution 
when entering the hatcher environment and in the present invention is 
particles in the range of one to one hundred microns in diameter. Any 
device which produces particles in this size range may be acceptable for 
the present invention. Particle sizes in this range may be generated by 
ultrasound using various ultrasonic humidifiers provided they are 
compatible with the solution to be used. Alternatively, the microaerosol 
may be generated utilizing specialized pneumatic driven nozzles such as 
those produced by Atomizing Systems, Inc. Thermal foggers or high velocity 
airstream with venturi nozzles may also be suitable to this application. 
The present invention is typically used in an incubator designed for 
hatching poultry or avian species including chicken, duck, quail, turkey 
or other fowl. 
The device to discharge the microaerosol may be located exterior to or in 
the interior of the physical hatcher unit, however the actual discharge of 
solution should occur in a location whereby maximum dispersal by the 
hatchers normal air flow will occur. Preferably this would be at the 
normal point of entry of air or humidity into the hatcher. 
The preferred solution in the present invention is hydrogen peroxide in a 
concentration of 1 to 3 percent. Levels of hydrogen peroxide above 3% may 
cause undesirable damage to tissues of the avian respiratory system when 
used in the present application. Incorporation of a stabilizing agent such 
as acetic or phosphoric acid in a concentration of 0.05%, maybe included 
to stabilize the effectiveness of the hydrogen peroxide in waters which 
are found to be incompatible with the ability to maintain hydrogen 
peroxide in solution. The commercial source of the hydrogen peroxide does 
not appear to be critical therefore any commercially available source may 
be used. In some cases it may be more convenient to stock concentrated 
H.sub.2 O.sub.2 such as a 50% solution may be more convenient than 3% 
solutions. The user can in this case dilute the concentrated solution 
prior to utilization, however, concentrated forms may be somewhat caustic 
or irritating to people. 
The solution dispersed utilizing the present invention need not be limited 
to hydrogen peroxide as will be demonstrated in an example to follow. The 
limiting conditions for a disinfecting solution used for the present 
method should be only its safety of use, effectiveness as an antimicrobial 
agent, minimal destructive properties to the tissues of the avian species 
being hatched as well as minimal destructiveness to equipment in which it 
is used. 
The time of implementation of the present method is preferably at the point 
when pipping or physical exit of the bird from the shell begins. The 
method is preferably employed continuously until a point in time just 
prior to removal of birds from the hatcher. Ordinarily it will be 
desirable to allow enough time for the particular hatcher used to remove 
any airborne disinfectant from the hatcher environment via the normal air 
exchange unit of the machine to eliminate possible irritation to some 
humans. 
The volume of the solution applied in a given time span will depend upon 
the type of hatcher used and the degree of air exchange in the given 
machine. The limiting condition on volume of solution applied is a volume 
which will effectively produce the desired antimicrobial action while not 
interfering with the normal relative humidity levels that are critical to 
the portion of chicks that survive the hatching process and to the post 
hatch performance. The volume of solution should also be able to be 
applied on a continuous basis during the hatch period. Advantageously, the 
microaerosol will also be applied in closed trucks that transport the 
chicks. 
In order to more fully demonstrate the attendant advantages arising from 
the present invention, the following examples are set forth. It is to be 
understood that the following is by way of example only and is not 
intended as an undue limitation on the otherwise broad scope of the 
invention.

EXAMPLE 1 
Affect of Microaerosol Administration of Disinfectant During Hatch Upon 
Hatcher Performance 
In this example a hatcher (manufactured by Chick Master Incubator Co.) was 
equipped with microaerosol producing nozzles (manufactured by Atomizing 
Systems Inc.), and calibrated in a manner to deliver 1 liter per hour of a 
solution of hydrogen peroxide. The nozzles were physically located on the 
inside of the hatcher in a position within one half meter of the machine 
humidity nozzle. 
Chicken eggs were transferred from setters on day 17 of incubation to the 
experimental hatchers in a randomized manner to eliminate variation due to 
pre hatcher incubation source. The application of microaerosol was started 
after physical exit from the eggs had begun, 48 hours from the expected 
pull time. Those skilled in the art will understand that "pull time" is 
the nominal time when the poultry is removed from the hatcher. This will 
ordinarily be the time after the chickens are dry. Control hatchers were 
set up in trial 1 to include one hatcher unit with normal formaldehyde 
fumigation by evaporation of 59 ml of formalin over 3 hours for a 30 hour 
time period starting 39 hours before the expected pull time of chickens 
from the hatchers. The second control hatcher received no treatment after 
the transfer was completed. Hatchery performance was measured by 
hatchability, bacteriological culturing of chicken down from the hatcher 
environment, histological examination of tracheal tissue of chickens at 
time of pull from the hatchers, physical appearance of the chickens at 
point of pull and weight loss between setter (eggs) and hatcher 
(chickens). 
As can be seen in Table 1, both fumigation with formaldehyde and 
microaerosol fumigation with H.sub.2 O.sub.2 significantly decrease the 
microbial contamination in the hatcher environment as measured by the down 
test method when compared to the untreated hatcher. Hatchability was not 
altered by method of treatment in the hatcher. The histological 
examination of tracheal tissue indicates that fumigation with hydrogen 
peroxide causes much less respiratory tissue damage than caused by the 
conventional formaldehyde fumigation method, however it does cause some 
tissue damage compared to the untreated chickens. The physical appearance 
of the chickens at hatch was altered by method of hatcher treatment in 
that chickens from formaldehyde fumigation had a dark yellow coloration 
compared to untreated controls, while those from the microaerosol 
treatment with H.sub.2 O.sub.2 had distinctly white (bleached) feathers, 
compared to untreated controls. All treatments produced chickens that 
other than color appeared active without any visible signs of respiratory 
distress. No difference was found between treatments in the amount of 
weight loss between eggs in setters and chickens out of hatchers, 
indicating that the microaerosol administration of disinfectant solution 
did not adversely alter the humidity level in the hatcher causing chickens 
to retain too much moisture. 
EXAMPLE 2 
Affect of Microaerosol Administration of Disinfectant During Hatch Upon 
Post Hatch Performance 
Experimental trials were carried out to examine the post hatch performance 
of chickens hatched with the various hatcher treatments alluded to in 
example 1 (trial 1), above. Sixteen experimental pens of chickens from 
each of the 3 hatcher treatments were set up with 128 birds per pen. The 
chickens were raised utilizing normal broiler growing methods in the same 
facility. Performance was measured in terms of growing mortality, live 
weight and feed conversion (in terms of pounds of feed to pounds of live 
chicken produced). The experiment was concluded when the chickens reached 
53 days of age. The experimental data is tabulated in Table 2. There 
appears to have been little difference in terms of live weight and feed 
conversion due to the various hatcher treatments, however the microaerosol 
administration of disinfectant (H.sub.2 O.sub.2), appears to have 
beneficial affects upon decreasing growing broiler chicken mortality. This 
decreased mortality rate was possibly due to the decreased microbial 
contamination in the hatcher compared to chickens from the untreated 
hatcher, or due to the lower degree of damage to the respiratory system 
than observed in chickens treated in the hatcher with formaldehyde 
fumigation. 
EXAMPLE 3 
Affect of Microaerosol Administration of Disinfectant During Hatch Upon 
Hatchery Performance 
This example is similar to Example 1 except that the disinfectant solution 
used was one percent glutaraldehyde in place of hydrogen peroxide. In this 
example hatchers manufactured by Chick Master Incubator Co. were equipped 
with microaerosol producing nozzles made by Atomizing Systems Inc., and 
calibrated in a manner to deliver two thirds of a liter per hour of a one 
percent solution of glutaraldehyde. The nozzles were physically located on 
the inside of the hatcher in a position within one half meter of the 
machine humidity nozzle. 
Chicken eggs were transferred from setters on day 17 of incubation to the 
experimental hatchers. The application of microaerosol was started after 
physical exit from the eggs had begun, 36 hours from the expected pull 
time. Control hatchers were set up to include two hatcher units with 
normal formaldehyde fumigation by evaporation of 59 ml of formalin every 3 
hours for a 30 hour time period starting 39 hours before the expected pull 
time of chickens from the hatchers. The second control hatcher received no 
treatment after the transfer was completed. Hatchery performance was 
measured by the portion of chicks surviving the hatching process, 
bacteriological culturing of chickens taken from the hatcher environment, 
and physical appearance of the chickens at point of pull. 
As can be seen in Table 3, both fumigation with formaldehyde and 
microaerosol fumigation with glutaraldehyde significantly decrease the 
microbial contamination in the hatcher environment as measured by the down 
test method when compared to the untreated hatcher. Hatchability was not 
decreased by the glutaraldehyde fumigation in the hatcher. The physical 
appearance of the chickens at hatch was not altered by method of hatcher 
treatment except that the formaldehyde fumigated chickens were more yellow 
in appearance than the other two groups. All treatments produced chickens 
that other than color appeared active without any visible signs of 
respiratory distress. 
EXAMPLE 4 
Affect of Microaerosol Administration of Disinfectant During Hatch Upon 
Hatchery Performance 
This example describes a variation of the present method whereby the 
microaerosol was generated via a Holmes Air ultrasonic humidifier which 
was placed inside a Chickmaster hatcher at the point chickens were 
starting to break out of the respective shells. A solution of 2.5% 
hydrogen peroxide was applied via the ultrasonic humidifier on a 
continuous basis for a 36 hour time period with an application rate of 
0.55 liters per hour. 
Chicken eggs were transferred from setters on day 17 of incubation and 
transferred in a randomized manner to the experimental hatchers. A control 
hatcher was set up which received no treatment after the transfer was 
completed. Hatchery performance was measured by hatchability, 
bacteriological culturing of chicken down from the hatcher environment, 
and physical appearance of the chickens at point of pull. 
As can be seen in Table 4 microaerosol fumigation with hydrogen peroxide 
applied via the ultrasonic humidifier significantly decreased the 
microbial contamination in the hatcher environment as measured by the down 
test method when compared to the untreated hatcher. Hatchability in this 
example was improved by the application of disinfectant into the hatcher 
environment. The physical appearance of the chickens at hatch was altered 
by method of hatcher treatment in that the hydrogen peroxide treated 
chickens had bleached (white) feathers following treatment when compared 
to the untreated controls. No signs of respiratory distress were observed 
in either group. 
TABLE 1 
______________________________________ 
HATCHERY PERFORMANCE DATA FROM VARIOUS HATCHER 
TREATMENTS 
Hatcher Chick 
Number Down Micro- 
Histological 
Hatcher Eggs in Hatch organisms 
Examination of 
Treatment 
Hatcher % per gram Tracheal tissue 
______________________________________ 
None 9558 65.8 &gt;30.000 Cilia intact, no 
glandular cell 
hyperplasia 
Fumigation 
9373 66.6 400 Extensive cilia loss, 
Formaldehyde epithelial disruption 
and capillary dis- 
tention with edema 
Microaersol 
9558 65.7 &lt;100 Some cilia loss, 
Fumigation distinct glandular cell 
2.5% H.sub.2 O.sub.2 hyperplasia 
______________________________________ 
TABLE 2 
______________________________________ 
POST HATCH PERFORMANCE DATA FROM VARIOUS 
HATCHER TREATMENTS OF 53 DAY OLD CHICKENS 
Number Live Body 
Hatcher of chickens 
Mortality Weight Feed 
Treatment placed Percent (Pounds) 
Conversion 
______________________________________ 
None 1984 6.96 5.288 2.248 
Fumigated 1984 6.70 5.280 2.237 
Formaldehyde 
Microaersol 
1984 5.24 5.280 2.231 
Fumigation 
2.5% H.sub.2 O.sub.2 
______________________________________ 
TABLE 3 
______________________________________ 
HATCHERY PERFORMANCE DATA FROM VARIOUS HATCHER 
TREATMENTS 
Number of Hatch Hatcher Chick Down 
Hatcher Eggs in Percent Microorganisms 
Treatment Hatcher of eggs per gram 
______________________________________ 
Glutaraldehyde 
9720 79.2 1,000 
None 9720 74.4 &gt;30,000 
Formaldehyde 
9720 73.6 &lt;100 
Formaldehyde 
9720 72.5 &lt;100 
______________________________________ 
TABLE 4 
______________________________________ 
HATCHERY PERFORMANCE DATA FROM VARIOUS HATCHER 
TREATMENTS 
Number Hatch 
Fertile of Hatcher Chick Down 
Hatcher Eggs in Fertile Microorganisms 
Treatment Hatcher Eggs % per gram 
______________________________________ 
None 5939 74.3 &gt;30,000 
Ultrasonic 
5862 78.4 400 
Microaersol 
Fumigation 
2.5% H.sub.2 O.sub.2 
______________________________________ 
The method in accordance with the invention provides a safe effective means 
of reducing microbial contamination from the environment after the poultry 
begin to hatch from the egg. In addition the method in accordance with the 
invention allows for the safe administration of disinfectant solutions 
with minimal exposure of people to the disinfectant. The application is 
capable of being automated to eliminate handling of potentially hazardous 
materials by hatchery personnel. 
It will be seen from the examples and descriptions above that the invention 
attains the following objectives. 
(a) Providing a reliable, efficient, and safe method for administering 
disinfectant solutions into the environment of hatching poultry after the 
point when actual exit from the egg begins, for the purpose of decreasing 
the level of microbial organisms in this environment. 
(b) Providing a method to allow continuous administration of disinfectant 
solutions into the environment of hatching poultry in a manner which does 
not introduce levels of moisture into this environment which would 
interfere with normal hatchability or post hatch performance. 
(c) Providing a method to administer disinfectant solutions which will 
minimize the damaging affects of the solutions upon the tissues of the 
avian respiratory system whereby post hatch performance will not be 
decreased and may be improved by said treatment. 
Other variations of the present invention will be apparent to those skilled 
in the art upon exposure to the teachings herein. For example, those 
skilled in the art will recognize, for example, there may be variations in 
the location of the source of microaerosol producing device, the type of 
device used to produce the desired particle range of solution to be 
administered, and the solutions used in the method will occur without 
changing the desired scope of the invention. Such other variations are 
deemed to be encompassed by the disclosure, the invention being delimited 
only by the following claims.