I cannot find any literature about amprolium side effects. Since it is a medication, I am sure there have to be some sort of side effects.. I have a five week old chick I have posted here a lot about that has been scratching her neck till getting it bloody since she was 3 days old. I tried antibiotics, neosporin, vitamin E, anti-mite products, the only thing that seemed to ease a bit the scratching was a few drops of Vitamin E on the skin and a few drops of benadryl given orally.. now since the benadryl seems to ease the itching I am assuming it may be an allergy, but to what? All she has been exposed to is paper towels, natural pine pellets, and the chick starter with amprolium.. since this started at 3 days old the only thing that comes to mind that could cause an allergic reaction is the amprolium added to her feed..before taking her off of it.. I was looking for any side effects listed.. but oddly cannot find any on the internet.. -I am ruling out something neurological since she was fine when we got her and the scratching started at three days old -I know it is not ear mites because I treated her with an anti-mite product and all the other chicks are ok.. if it were mites they would be all itching as well -I know it is not an ear infection as she was on an antibiotic for 10 days (duramycin) -It is not feathers growing since it is extreme where she cries, scratches and at times tosses her self on the floor, no other chick does this -It is not a vaccine reaction to the Marek's shot as my hatchery suggested since by now it would have been gone. All that remains is an allergy to something.. and the amprolium is the only thing that comes to my mind..