My 7 weeks olds have been on the ground since they were 4 weeks. Some of them are doing the wide open mouth thing and I'm worried they may have gapeworm. Would it be safe to give them the drops of ivermectin on their backs? I started the AVC and garlic water at age 2 weeks. Med feed. I throw a little DE in there feed here and there too. They run around and play in the barn which has a limestone floor. Was thinking they may be eating peices of that.?? They are my leghorn pullets I have worked so hard on and I want them to be as healthy as possible. Thanks!! Also, I have a couple older birds who are snotty, foamy eyes and weezey? Any suggestions on that??