What is the youngest age you can treat chicks for possible mites? We have some 1 week olds, 2 1/2 week olds and 3 1/2 week olds in the brooder. A couple of the 3 1/2 week olds are exhibiting behavior like they are picking mites off each other. Are they too young for dusting with Sevin? I could put it in their pan of soil they dust bathe in, so I don't have to dust them directly. They can get it while dustbathing. But, are they too young? I don't want it to harm them.