Just got back from the Vet he gave me this medication and said add 2 tablespoons into 1 gal water and let it be the only water source has anyone ever heard of this medicine before because I've never used it but I'm sure the vet knows what he's doing,I read on that package not to use on laying hens all the birds are together but the free range also, So will this medication hurt the laying hens??
SMZ, is a sulfa drug often used to treat Coccidiosis, Coryza, and some other respiratory diseases in birds. The warning you see on the packet is stating there is meat and egg withdrawal for the drug. I believe there is only a ten-day meat withdrawal, but they do suggest never eating the eggs again from the birds that were treated ( a lot of people don't follow this suggestion and eat eggs using the same withdrawal time as the meat).
Here is some info on SMZ,
https://www.drugs.com/vet/smz-med-454.html