10/5/20

Defend the Flock 

Introductions

Hello, everyone. Thank you for joining the webinar. 

Today's presentation, Defend the Flock, Controlling 

Salmonella in Commercial Poultry Through Biosecurity is 

part of the Defend the Flock campaign. We are here today 

to support you and your flocks with biosecurity resources. 

I'm Dr. Taylor Gaines. Today I'm joined by my colleague, 

Dr. Kathryn Burden, laboratory coordinator for the National 

Poultry Improvement Plan, and Dr. Charles Hofacre, 

president of the Southern Poultry Research Group and 

professor emeritus at the University of Georgia.

A few housekeeping items before we get started. First, 

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Now we will take a few minutes to introduce ourselves.

I'm Taylor Gaines, I'm a veterinarian in the US poultry 

health team. I graduated with a DVM and a Master of 

Public Health from Virginia Maryland College of Veterinary 

Medicine. Dr. Burden tell us a little bit about yourself.

>> Thanks so much, Dr. Gaines. Hey, everyone, my 

name is Dr. Katy Burden. I'm the laboratory coordinator 

within National Poultry Improvement Plan. I got my DVM 

from the University of Georgia and I have a bachelor of 

poultry science and in dairy science.

>> Dr. Hofacre?

>> I'm Chuck Hofacre. I got my masters in poultry 

science and DVM from Ohio State, and master's in Avian 

Medicine and PhD from University of Georgia, the first 

veterinary that Ross breeders had in the United States, and I 

was at the faculty at the vet school for 18 years.

>> Thank you, Dr. Hofacre. Now we will turn things 

over to you to begin our discussion about Salmonella and 

how it affects poultry.

What is Salmonella?

>> First off, Salmonella is a gram-negative bacteria, it's 

a bacteria that's in the same family as the bacteria that 
causes airsacculitis most frequently in broilers and that's E. 

coli, so Salmonella is in that family, two major groups, there's 

typhoids that cause disease in chickens and the 

paratyphoids, those are the ones that we will spend most of 

today discussing. Those are the Salmonellas that can lead to 

food borne illness in people.

This quote from Doctor McCapes, from the proceedings 

of a Salmonella symposium is one of my favorites, it sums 

up what we are trying to fight against as we try to control 

Salmonella, it's an organism that has a simple life. It tries to 

find an intestinal tract of a host animal. And that can be 

multiple different species, it doesn’t have to be a chicken.

Multiply in that intestine and then get out of the host intestine 

and then find another host intestine to get into. 

So, Salmonella are not all the same, there's 2,500 

different Salmonella serovars within those paratyphoids. 

And just like people, not all those Salmonella behave the 

same. Some are heat tolerant, some live only in the 

intestines and won't get into the internal organs, some 

survive a long period of time for years in a dry environment. 

We can't think of Salmonella as all being the same. 

Therefore, the strategy that we put in place to eliminate or 

reduce the level of Salmonella in our flocks may vary with 

the Salmonella serovar that we have infecting those flocks. 
Next slide, please.

We can't forget the typhoids, because the typhoids, 

Salmonella pullorum, Salmonella Gallinarum, nearly wiped 

out the broiler industry and breeder industry in the United 

States in the 1930s, it's really the impetus for the creation of 

the National Poultry Improvement Plan. Because these two 

types are, they specifically infect chickens, they won't make 

people sick, but they will kill hens. So adult chickens can be 

killed by this. It will have a negative impact on their body 

weight, reduced egg production and the typhoids are 

diseases that we have tried to eradicate from poultry in the 

United States.

An example, one of the old names for Salmonella 

pullorum is bacillary white diarrhea, bacteria diarrhea in baby 

chicks, you can see that picture in the left, that's Salmonella 

Gallinarum, it makes baby chicks sick if they get Salmonella 

pullorum or Gallinarum from the hen.

Next slide. 

So, let's talk more about the paratyphoids, next slide.

Sources of Salmonella and How it Spreads

The sources of Salmonella for, are hens or for broilers 

is a long list. Because Salmonellas aren't specific host in a 

chicken. And we will talk some about each one of these. 
Next slide.

Keep in mind that Salmonella can be transmitted from 

one generation to the next generation. That's why NPIP 

began working with the elite pedigrees and the GGP's and 

the grandparents of the primary breeders so we stop this 

could from coming down through the chain. We also want 

to look at the paratyphoids, to try to keep them from 

transmitting from one generation to the next and getting all 

the way down to the consumer and causing food borne 

illness.

Next slide.

So, I will give you an example of why I think Salmonella 

can be transmitted from one generation to the next. Doctor 

John and I did a study many years ago, what we look at 49 

poultry farms made 200 almost 40 farm visits, collected 

almost 7500 samples, and 1600 isolates of Salmonella. We 

also had the primary breeder for that broiler company supply 

us with Salmonella isolates so we can see through the 

generations. And what we found was the next slide, please.

That the major Salmonella was Salmonella Kentucky. 

And we fingerprinted it and we called it Salmonella Kentucky 

number one. We found others, but that Salmonella 

Kentucky number one, that fingerprint was exactly the same 

Salmonella that we found in the primary breeders, we found 
it in the pullets, we found it in the adult hens, in the broiler 

house, and we also found it in ceca in the processing plant. 

So, the same type, Salmonella Kentucky was being 

transmitted all the way through multiple generations all the 

way to the processing plant.

That's why it's important for us to reduce or eliminate 

Salmonella at each of those steps through the broiler 

production chain.

Next slide, please.

So, is Salmonella actually truly egg transmitted? 

Doctor Richard Gast at USDA here in Athens, Georgia, 

looked at the true transovarial transmission of SE he infected

hens with SE cracked the outside of the eggs and cultured 

just the internal eggs, one in 20,000 eggs had Salmonella on 

the inside. We know the rate of transmission is higher than 

that. My opinion, why so much Salmonella ends up going 

through the generations, is that as the egg cools, the hen 

lays an egg, the temperature is, say 150 degrees, the 

outside temperature is 46 degrees, the minute that egg 

comes out of that hen, it begins to cool. It begins to cool 

and suck air in from around that nest, wherever that egg is 

being laid. Or if it's on the floor, floor eggs. In the 

summertime, if we have eggs in a cooler, and take them out, 

what happens when you have a glass of iced tea in the 
summertime and you walk outside? It sweats. Well, that 

sweating allows bacteria to get into that egg. So, egg 

cooling, egg sweating, cleanliness of shell eggs, is very 

important for us to reduce the transmission of Salmonella 

from one generation to the next.

Next slide, please.

Controlling Salmonella

To me, controlling Salmonella is a numbers game. We 

want to reduce the number of Salmonella that our flocks are 

exposed to, we can reduce it by biosecurity, by reducing the 

Salmonella in inputs into that flock or by the interventions 

that we put in place to help reduce the level of Salmonella 

that our hens are exposed to. A hen that's older can keep 

from becoming infected with Salmonella by, as many as 100 

to a thousand Salmonella cells by some of the, by normal 

flora and by other immune responses say from vaccinations. 

So, if we keep the numbers low, then the natural protective 

mechanism by the older bird can help reduce the chance of 

colonization. Next slide, please. How can we control 

Salmonella in our poultry? Well, once Salmonella is 

established in a flock of birds, it's nearly impossible to 

eliminate that Salmonella. So, our goal needs to be, don't 

let them be infected in the first place. Even antibiotics 
cannot be very successful in eliminating Salmonella positive 

flocks and making them become Salmonella negative.

So, once introduced, once a flock is Salmonella 

positive, it's difficult to eliminate and we have to test the birds 

or their environment to determine if Salmonella is present. 

And one way to test a breeder hen environment or breeder 

hen flock is to culture the chick papers from the hatchery. 

Because if they have transmitted it to the next generation, it 

will show up in that meconium, the first feces from baby 

chicks.

Next slide.

A flock of hens that is positive for Salmonella really the 

only opportunity to eliminate it is to eliminate that flock of 

hens. That seems pretty harsh, but in my experience of 

dealing with Salmonella for almost 40 years, is that once a 

breeder flock is positive, they are always going to be positive 

and they will intermittently shed. It can take a long time to 

eliminate Salmonella by this stamping out method. But in 

reality, that's the only way to do it, to eliminate it, especially 

those that can cause human illness like Salmonella, 

typhimurium. So, biosecurity is not going to completely 

eliminate the risk but help us reduce the numbers.

Next slide. So, this student whose now a veterinarian 

over in the UK, I asked him to stand in front of a mirror, I 
want you to stand in front of a mirror, you as a poultry 

manager, are the most critical factor, the decisions you make 

in managing your flocks are critical in your success to control 

Salmonella. Next slide.

How to prevent Salmonella from getting into our flocks

So, how do we prevent Salmonella from getting into our 

flocks? Next slide.

If that square box in the center is our chicken house, 

and we have a brand new chicken house, never put any 

chickens in there, never put any feed, never go into that 

house, don't let any insects get in there, we are not going to 

have Salmonella in that house. But the minute we bring in 

chickens or people or litter or feed or let rodents or wildlife 

get in this there, we have the opportunity for Salmonella to 

come in there. Rather than focusing on all those things at 

once, let's break it down and look at those areas that may be 

the most critical for us, for one complex, insects may be the 

big problem. For another complex, it might be vehicles. Or 

people. So, it's not always the same in every location, nor 

is it the same for every poultry house.

Next slide.

Flies. Since you were a child, what do you do when a 

fly lands on our plate? You are out having a picnic. You 
shoo it away, because your mother told you flies carry 

germs, well, Salmonella is a germ, and flies can carry 

Salmonella for as far as three miles. Just the common 

house fly can be a source of Salmonella. Next slide.

Darkling beetles, I don't think there's a chicken house in 

the United States, maybe very few in the world that don't 

have darkling beetles. These guys live down in the litter, 

they burrow in the litter and burrow into the dirt floor, they will 

do it through seven stages, those worm looking things are 

the pupa, and the adults are the dark black beetle. And that 

is the gizzard of a baby turkey. If I were to put a pile of feed 

in front of a bunch of chickens or turkeys, which do you think 

they are going to eat? They are probable going to eat the 

beetles, they look for things scurrying around. University of 

Arkansas found that Salmonella typhimurium can live in the 

intestines of a beetle for at least of 60 days, it might be

longer. So if we have a downtime of 60 days, that doesn't 

necessarily mean that we have gotten rid of all the beetles, 

we may have cleaned and disinfected but if the beetles 

come back in and they can still have Salmonella in their 

intestines and a chicken eats the beetle. We haven't made 

a whole lot of headway. Next slide. There are three 

species of rats and mice that live and can be commonly 

found in chicken houses in the United States. The roof rat, 
the Norway rat, and the house mouse, understanding their 

behave and location and understanding which one you have 

in your poultry house will help you know how to control them. 

For example, the roof rat, where do you think they live? Up 

in the roof. They live in that false ceiling, they live in the 

insulation, they come down the wires suspending the 

feeders for water and eat and drink and go back up. Their 

feet never touch the ground. If I put rat bait all around the 

perimeter of my poultry house, are they going to kill roof 

rats? No, they never go there. We need to know what type 

of rodent we have infesting our poultry house to know how to 

properly eliminate them.

And it might be Norway rats on one farm, and another 

farm, five miles down the road, might be roof rats or it may 

be the house mouse. Next slide.

Kate Hayes, which she was working on her master's, 

was trying to understand that concept of how important it is 

to control rodents. So, around their breeder farms, they had 

bait stations, about it stations tin traps, the traps that catch 

them and don't let them get back out. She counted the 

numbers and she monitored the level of mice and as you 

can see, the number went up in the fall, came back down in 

the winter and spring, back up in the fall the next year, came 

back down. Why do you think the number of mice would 
come up in the fall? Why is it, we probable will see more 

mice inside of our poultry houses now than we did two 

months ago? It's because it's getting cool, they are looking 

for a warm place to eat and we are harvesting crops, when 

we do that, we disrupt their habitat and they look for a nice 

safe place, like a chicken house. Next slide.

So, Kate cultured the inside of those boxes and 

Salmonella levels inside of those boxes came up in the fall 

and went down in the winter. Back up in the fall, down in 

the winter. Where is Salmonella coming from in those bait 

boxes? From the mice. The mice are bringing Salmonella 

and are a big risk for us on all our farms. Next slide.

Cleaning and disinfecting. I didn't write this list as an 

exhaustive list; this is what you have to do. I wrote it as an 

example of things you can do, but I want to emphasize, 

whenever we clean out, let's say a broiler breeder house, we 

are going to take out the slats, remove the litter, blow down, 

maybe wash down, where do you think the mice went that 

were down under the slats living down in the droppings from 

the hens? They went away. When we take those slats 

out, they go away. Where do they go? Next door, they go 

in the woods, they go into the walls. Then when the house 

warms back up and everything is setback up again and 

there's food and water for them, where do you think they 
come? They come right back in again. So, we want to bait 

for rodents the minute the birds leave the house. That way 

they are accustomed to eating and drinking and would 

replace it with bait and that helps reduce the risk of them 

running away and coming back again.

We want to have our insecticide as the last thing we do 

before we bring in litter. Why? Because those beetles are 

migrating away, same way, but we can't bait them in the way 

we do the rodents, but if we put a barrier of insecticide so as 

they come back in, they have to go through that barrier of 

insecticide, residual insecticide and it will kill them. That way 

we kill them before they come in and live and reproduce and 

infect our flocks. Next slide.

Feed. I have been involved in one large outbreak that 

was associated with feed. The initial introduction was by 

feed, but it wasn't maintained by the feed. So, feed can be 

a source of Salmonella. Especially for your breeders, it's 

important that we understand that and minimize the risk from 

the types of ingredients we use to pelleting our breeder 

feeds and the use of organic acids and formaldehyde 

products. So, I could spend a whole talk just talking about 

feed. So, keep in mind, though, that our feed source can be 

a source of Salmonella.

Next slide.
Water. Birds drink twice as much water as they eat 

feed. So, if they eat one and a half pound of feed, they are 

going to drink three pounds of water. Or almost a half a 

gallon of water, per bird.

And if that water source has Salmonella in it, then they 

are going to drink Salmonella. But also if you look at that 

nipple drinker, even though water flows out, Salmonella can 

get up inside of those water lines, if you ever cut a water line 

and run your finger on the inside of it, that slippery slimy film 

is bio film and Salmonella makes bio film and Salmonella 

can live inside those water lines. So, chlorination and water 

disinfection is important for us as a Salmonella control 

program. It's even an easy thing to do. Next slide.

Last topic I will talk about is poultry litter. Like every 

living organism, Salmonella needs water to survive and 

reproduce. I did say there are some that can live in dry 

environments, but they won't reproduce. And if the water 

activity in the litter gets above 25 percent, that's enough 

water for Salmonella to reproduce. We want to try to keep 

water activity low. That will keep Salmonella from 

reproducing. It won't kill it, but it won't reproduce. Another 

thing about Salmonella, just like E. coli and some of the 

other pathogenic bacteria, they like an alkaline environment, 

high PH litter environment. We want to do things that we 
drive the PH of the litter down and use products like 

propionic acid and aluminum sulfate to keep that PH low so 

it's less than a happy place for the Salmonella to survive and 

reproduce. With that I will be happy to turn over the 

program to Dr. Burden.

>> Thank you, Dr., as always that was very informative. 

The next part of this presentation is going to focus a lot on 

what you can do within the house to help mitigate 

Salmonella, I'm going to go ahead and apologize, this part I 

get really excited about. So, I'm going to try to speak slowly 

so that everybody can hear me, and I speak clearly. But so, 

we will just jump right in on this slide.

There are a few things that I like to do when I go into a 

chicken house, and that's actually to look around and see if 

we have got anything that doesn't belong there. So, one of 

my favorite pastimes is to go in at night or to go in with some 

of the people that work there and kind of see how they 

handle themselves inside the house. On this slide we 

actually have a picture of a pine ciscan and some of you 

may know that in 2009, there was a large surge of the pine

ciscans in the eastern US. What happened there was a lot 

of those pine ciscans had some type of pullorum we do have 

some birds, there was a American gold finches that died in 

1998 because of Salmonella so there are those wild birds 
and song birds that can get into the house and wreak havoc. 

Just a few things that I have seen in houses and all them 

can carry Salmonella, I have actually seen pets walking 

through houses with owners, I have seen dogs that are used 

as retrievers, almost, to find dead birds in the house. I have 

seen cats that have been used for rodent control. And 

that's, while a cat might actually be able to catch some mice, 

that's kind of frowned upon, because it's really hard to swab 

a cat's rear end to make sure that they aren't carrying 

Salmonella. That's always a fun time to try to swab a cat's 

rear end. The other thing that we have seen, I have seen a 

skunk in a house, early morning, that was kind of weird, 

armadillos, sparrows and finches. Next slide, please, 

ma'am.

So a few other things that I have seen, I have seen 

snakes, I have seen multiple robins that are usually nesting 

on the eaves of the house on the outside and on the fans 

and grills and stuff like that. I have seen pigeons, a lot of us 

know that, or if you didn't know, pigeons can also carry 

Salmonella and spread it around. A lot of the times it’s

Salmonella typhimurium they have but there can be other 

Salmonellas as well. Just like Dr. Hofacre was saying, mice 

and rats throughout the house, you will see different times. 

I have seen a lot of them when you clean out a house, they 
run to the house next door or run to the house across the

street so that they can continue to eat and feel safe in the 

chicken house. So, baiting before you actually clean out is 

a great idea to keep those mice and rats from moving. Next 

slide.

So, some of the things you can actually do when you 

are talking about a commercial poultry house is, you can go 

in and you can either go in at night or go in during the day 

and make sure that all the lights are off, it's not bright in 

there, and you can see where light is leaking through in the 

house.

So if you have got a curtain sided house, which some of

our older houses are like that, the houses in the Midwest and 

out west are still like that, that poses a large opportunity for 

things to get into the house because you got a curtain sided 

house instead of a solid wall house. You can see if there's 

any light that is actually coming through into the house. 

That's where you need to pay attention to make sure that 

this wildlife is not getting in.

The last thing that you could do is, look at structural 

problems for the house itself. Next slide.

So, what we mean by structural problems is, with our 

older houses or areas where erosion is prevalent, you might 

see that, some of your foundation is starting to get exposed. 
Make sure that there's no holes down in the foundation or

cracks in the foundation for animals to get in. The further 

away vegetation is, the less likely you are going to have a 

habitat or place for snakes, rats, or mice to hide in. If you 

put a little bit of gravel out there or concrete pad to keep that 

vegetation away or keep the grass cut really short, you can 

help deter pests from making their way into the house. You 

also need to make sure that you know where your 

biosecurity areas start and make that evident so you are not 

actually bringing in your pets or not actually bringing in pests 

that don't need to be in there.

One of the things that you need to pay attention to on 

the outside of the house, this goes for the backyard 

because they experience it as well as well, you need to 

make sure that there's no wild birds that are hanging out in 

the eaves of your house. You need to look, if you see any 

robins’ nests, see any sparrows, pigeons, make sure you do 

something to keep the wild birds off the sides of your house. 

Next slide.

So, some of the things that we can do to actually 

prevent Salmonella from infecting your poultry, it has to do 

with your equipment, shoes, and clothing. If you have got 

residual bacteria from a previous swab, the Salmonella can 

actually be found in that fecal material and that dust material 
that's still in that house. You need to try to clean the 

surfaces before the disinfectants are applied. This helps to 

improve the efficiency or the effectiveness of the 

disinfectant. Going back to what Dr. Hofacre told us, we 

need to do some sort of the cleaning before the disinfectant. 

And the equipment and clothing, if you are using the same 

between multiple houses, you can increase the production 

from one house to the next. Next slide.

Another thing to think about is actually how you are 

going to handle dead birds in the house. So, your mortality 

and morbidity, the dead birds you all should remove them in 

a timely manner and dispose of them appropriately. 

Carcasses can serve as a reservoir for Salmonella and can 

infect all the other birds in the house. Personnel should try 

to work from the healthiest birds or the youngest birds to the 

sicker or older birds to reduce the potential for spread.

Know the status of your spike males, your replacement hens 

or your replacement pullets and if you are working 

exclusively in Turkey operations, you need to know if the 

semen you are using for artificial insemination is 

contaminated prior to bringing it into the house. Next slide.

One of the biggest things that you can do is, you can 

actually rely a lot on training. So, are you training the 

people that work on your farm? They should all be trained,
and they should adhere to standard operating procedures. 

Usually the standard operating producers are created by 

identifying potentially risky situations such as the business.

Does this person have birds at home? Make sure they don't 

have the dangerous contact or those high-risk contacts. 

Sometimes we will see that people will have pet birds at 

home and they don't tell their employers and they will 

actually bring something into the chicken house. Well that's 

super risky. The 14 biosecurity principles can help 

producers identify these potential areas of risk. Next slide, 

please.

So basically, when we are talking about Salmonella, 

and we are talking about biosecurity, biosecurity is a 

supplementary measure to keep diseases out of the house 

but is also a method to keep other houses from getting a 

disease. Mainly for Salmonella, we are talking about birds 

that might already have it so your biosecurity will actually 

help reduce introduction of new Salmonella serotypes and 

will keep your neighbors from getting your Salmonella.

Next slide, please.

Now I'm going to turn it back over to my colleague, Dr.

Gaines and he will talk more about the biosecurity resources 

that are available from USDA APHIS.
New Resources from USDA

TAYLOR GAINES: Thank you, Dr. Burden and Dr. 

Hofacre. I will conclude our presentation with an overview of 

the resources available through USDA APHIS that will help 

you implement some of the biosecurity practices that we 

have discussed here today.

APHIS veterinary services have developed a library of

checklists that provide practical tips and recommendations, 

we encourage you to visit the Defend the Flock website to 

view and download these materials. All the checklists are 

available in multiple languages including Spanish, Chinese, 

Vietnamese, and Tagalog. On our website you will find lots

of free tools including recordings of prior webinars, 

newsletters and videos and other resources, we are excited 

to announce the Defend the Flock calendar is back for 2021. 

To order, please visit bit.ly/APHIS_publications and search 

for PA-2261. You can also go to our home page and submit 

a photo for a future calendar. APHIS has also created

social media content to help promote biosecurity, 

infographics covering many of the best practices that we 

covered here today are available in English and Spanish. 

We hope that you will share these with your colleagues and 

fellow poultry keepers on Facebook, Twitter, Instagram, and 

other social media channels to make sure people are using 
biosecurity every day, every time, no matter the size of the 

flock.

Be sure to check out more helpful information on our 

social media channels. This presentation along with 

answers to your questions will be available for downloading 

from the website shortly. Be sure to follow Defend the Flock 

on Facebook and Twitter to be notified when the 

presentation is available. And use the hash tag flock 

defender when sharing or posting information to help spread 

the word that biosecurity is the best way to keep flocks safe 

from Salmonella and other infectious disease. Before we 

go, on behalf of APHIS, thank you, Dr. Burden and Dr.

Hofacre, for sharing your valuable insights and knowledge 

with us today. And thank all of you for joining us on this 

webinar. And let's keep our poultry healthy together.