Q: How can I tell if my flock is infected with Salmonella? What are the symptoms?
A: While you won't be able to make a firm diagnosis of Salmonella on your own, it will be easy for you to see that your hens are sick. Chickens sick with salmonella will be weak, lethargic, have purplish combs and wattles, a decreased appetite and increased thirst. Plus you will see distinct white, sulfur yellow or green diarrhea. In some cases, joints might be swollen and blindness might occur from swelling in the eyes. If your birds were laying, production will be drastically reduced. But these symptoms can also indicate other illnesses, so you'll have to consult a vet to get a firm diagnosis.
But even if you didn't know that the symptoms listed here can indicate salmonella, common sense would tell you something is wrong if you saw this occurring in your flock! It just isn't something that's hard to spot.
The reason that HUGE outbreaks of salmonella occur in large factory farms, the reason that it gets to the point of enormous recalls involving millions-of-eggs, is because factory farms do not care properly for their birds. They don't notice when the birds get sick, because if the birds are in tiny cages, it's not as if they can then identify that the birds are any more weak or lethargic than usual in the conditions provided. Factory farmed birds can't normally even stretch their wings because the cages are so small.
Workers at factory farms don't monitor appetite for a single bird. They won't notice when a chicken doesn't seem to be foraging as much as usual, because their birds are fed on conveyor belts. And they aren't really monitoring droppings, either.
Remember, factory farms are places where DEAD bird are often not noticed for many days. If you have a strong stomach, you can Google for more information about this.
But remember too that your chickens don't have to be sick with salmonella to pass bacteria to you. Salmonella bacteria are found in small concentrations nearly everywhere in the environment; it occurs in cat poo, dog poo, wild bird poo... and human poo. So when you pick up your bird who has been walking in and pecking around poopy litter, amke sure to wash your hands... the same way you'd wash your hands if your dog--who has been nibbling on canine-enticing cat poop in the yard--licks your fingers with conditionless, unbounded doggy love. Use common sense. For more info, we have a great blog post on the topic of salmonella and backyard chickens that will be helpful.
Let's be honest: anyone can have a pet get sick. No matter how well you care for your pets, you can't protect them from everything. But commercial entities don't take the same kind of care of chickens as you do at home; small backyard flock owners usually know the name of every bird they keep, and take extraordinary care of their beloved pets. If you do see symptoms that concern you, we recommend contacting a vet to get a firm diagnosis, since the symptoms of Salmonella infection can be indicative of other illnesses, too, such as Colibacillosis or Newcastle. In any case, your birds will need veterinary attention when they have these symptoms.