okay, so i have a new flock of 16: 5 week old babies and about 1 week ago i noticed one of them had a droopy eye. It took me 2 days and research to figure out it was a respiratory issue and needed to isolate her. I started her and the rest of the flock on Tylan 50. after all was said and done 3 birds had visible symptoms and I isolated 4 in total (the 4th is just off in general, she has a crooked beak, nervous system issues and acts a little wacky). Anyway, I'm not sure what to do now. I am not going to cull my entire flock and start over, so thats not an option. So do i cull the ones that had visible illness? will my flock still have to be a closed flock? do i just re introduce them once I know they are 100% better? is there a set time period for that? and if it makes any difference here are their symptoms: droopy eye with bubbles, some slight swelling under the eye, and a reaching gag. No one lost appetite or lost weight or was lethargic. no chicks died.