not jumping to conclusions but u might have CRD!!! the birds that have it will all be carriers for life and there is no cure but u can get treatment but it will only temporarily stop it. the birds that have it will allways be carriers as i said. If there is any other birds in with them that dont have this keep them in with the iffected ones do not take them out and put into another house with other chickens they may have it aswell they mightnt show symptoms but you may have to wait a few weeks to check if they have the symptoms.
it doesnt affect the birds eating or interaction with the other birds and it wont kill them.
but if you dont want your flock to all get it cull the ones that have it(im sorry to have to say that)
Hope its just a lil cold. Maybe pull the sick ones and keep them seperate. Might go to the feed store for some help with meds. Tell them whats going on and they will have something for them. Good luck!
I have had to give them tylan injectable when we had it here.
Control of chronic respiratory disease (CRD air sac disease) caused by Mycoplasma gallisepticum and Escherichia coli, infectious synovitis caused by Mycoplasma synoviae susceptible to tetracycline hydrochloride.
CRD AIR SAC DISEASE: Use soluble powder in the drinking water at a drug level of 400-800 mg tetracycline hydrochloride per gallon per day.
INFECTIOUS SYNOVITIS: Use soluble powder in the drinking water at a drug level of 200-400 mg tetracycline hydrochloride per gallon per day. (Administer for 7-14 days).