A long period of time would be month after month with these medicated feeds.
However if you are raising these birds to eat, I would definitely be careful with what you feed them. Amprolium is a thiamine blocker and won't hurt you. But any other antibiotic will linger in the tissues for a certain period of time. So always check on the meat and egg withdrawal for all meds before butchering or consuming meat or eggs.
However if you are raising these birds to eat, I would definitely be careful with what you feed them. Amprolium is a thiamine blocker and won't hurt you. But any other antibiotic will linger in the tissues for a certain period of time. So always check on the meat and egg withdrawal for all meds before butchering or consuming meat or eggs.