The age of this particular one is a turken and is 4-5 weeks old about. First symptoms these birds start out with is ruffled feathers and lack of activity.Welcome to BYC. Can you please give some details of symptoms you are seeing, age of chicken, and anything else that can be helpful? The picture shows a lot of feather loss. Can you explain more about it?
I would treat them all with the Corid. Dosage for a severe outbreak is 1.5 tsp of the powder or 2 tsp of the liquid Corid per gallon of water, mixed fresh as their only water source daily for 7 days. After finishing, give vitamins in their water. Make sure the sick ones are drinking plenty of the water. I would separate the turkeys and ducks from the chickens, and provide them with water to dip their faces into to keep their nostrils and eyes clean. I know little about ducks or turkeys, but they need to be separated during this time. Let us know what happens.