"You only get salmonella from chickens that are sick with it themselves. You would typically notice a salmonella problem in your flock." - Statement found on a Facebook chicken group posted on April 30, 2015.
Salmonella can come from multiple sources, not just
chickens. You can get it from fruits and vegetables, as well as from your
flock. Cross-contamination in the kitchen is also another way to get sick
with Salmonella, or any other bacteria for that matter. If you do not
keep certain foods refrigerated and then undercook the food, then that is
yet another way to get sick with Salmonella. The blame is not always on
the chickens! Salmonella has lots of ways to get into us if we do not
know how to safely handle foods in the kitchen.
Now that that is out of the way, let’s talk about the chickens. You said “"You only get salmonella from chickens that are sick with it themselves.” That statement is correct. Salmonella on the inside of chicken eggs typically comes from the chicken that is sick with the organism. However, you can get Salmonella on the outside of the egg if the coop that the egg is kept in contains Salmonella. That means another chicken could be sick with Salmonella and be spreading it around in the coop. Dirty bedding, dirty nest boxes, dirty egg collections baskets, or other surfaces in the coop can be a source. We all know that our chickens tend to share nest boxes, so think about it. If the infected chicken uses the same nest box as a healthy chicken, then the outside of a good egg can be contaminated just through contact. That is why we wash our eggs, so that the bacteria does not work its way in through the eggshell’s pores to contaminate the inside (or our hands as we crack open the eggs).
You also said “You would typically notice a salmonella problem in your flock." This is not as accurate as your previous statement. Salmonella has several hundred different serotypes, very few of which cause the chickens to show symptoms of illness. Instead the chickens can become carriers of Salmonella. That means that they randomly shed the bacteria in their feces, and their eggs, without showing signs that they were ever sick. Salmonella is famous for this feature in humans too. Ever heard of Typhoid Mary? Same bacteria, just in humans rather than chickens. The only way we know if our chickens have Salmonella is to test them regularly, because if we lapse in our biosecurity, then our chickens can pick up Salmonella at any given time.
Now that that is out of the way, let’s talk about the chickens. You said “"You only get salmonella from chickens that are sick with it themselves.” That statement is correct. Salmonella on the inside of chicken eggs typically comes from the chicken that is sick with the organism. However, you can get Salmonella on the outside of the egg if the coop that the egg is kept in contains Salmonella. That means another chicken could be sick with Salmonella and be spreading it around in the coop. Dirty bedding, dirty nest boxes, dirty egg collections baskets, or other surfaces in the coop can be a source. We all know that our chickens tend to share nest boxes, so think about it. If the infected chicken uses the same nest box as a healthy chicken, then the outside of a good egg can be contaminated just through contact. That is why we wash our eggs, so that the bacteria does not work its way in through the eggshell’s pores to contaminate the inside (or our hands as we crack open the eggs).
You also said “You would typically notice a salmonella problem in your flock." This is not as accurate as your previous statement. Salmonella has several hundred different serotypes, very few of which cause the chickens to show symptoms of illness. Instead the chickens can become carriers of Salmonella. That means that they randomly shed the bacteria in their feces, and their eggs, without showing signs that they were ever sick. Salmonella is famous for this feature in humans too. Ever heard of Typhoid Mary? Same bacteria, just in humans rather than chickens. The only way we know if our chickens have Salmonella is to test them regularly, because if we lapse in our biosecurity, then our chickens can pick up Salmonella at any given time.
Response provided by Dr. Brigid McCrea, Ph.D.
Associate Professor and Extension Poultry Specialist
Delaware State University
