BelovedBirds
Crossing the Road
Ive heard that because ducklings eat more than chicks, they can overdose on the medication, it isn't the medication itself that's harmful but the dosage-X2. Another medication that is safe is bacitracin. Last year my brooder raised ducklings were feed with bacitracin, and a few years ago I fed feed with amprolium and bacitracin.
Medicated feed is fine for all waterfowl.
That's what I've heard