Thrush with chickens is very similar to thrush that babies get.
You’ll notice a white oozy substance inside their crop (which is a space between their neck and body.) They will have a larger than normal appetite. The chicken will appear lethargic and have a crusty vent area. And their feathers will look ruffled.
It is important to mention that thrush is a fungal disease. This means it can be contracted if you allow your chickens to eat molded feed or other molded food. And they can also contract the disease from contaminated water or surfaces.
Though there is no vaccine, it can be treated by an anti-fungal medicine that you can get from your local vet. Be sure to remove the bad food and clean their water container as well.
2. Air Sac Disease
This disease first appears in the form of poor laying skills and a weak chicken. As it progresses, you will notice coughing, sneezing, breathing problems, swollen joints, and possibly death.
Now, there is a vaccine for this illness, and it can be treated with an antibiotic from the vet. But it can be picked up from other birds (even wild birds) and it can be transferred from a hen that has it to her chick through the egg.
So just keep an eye out for any of these symptoms so it can be treated quickly and effectively.