My babies are dying on me, and I can't pinpoint why!!!! We had a couple sudden deaths, with no symptoms beforehand. Then a few started to get puffy eyes, and were acting lethargic. We've treated the coop for mites/lice with Permethrin, bc I thought I saw something crawling on one of the sick babies. We put Corid in their water, treated with Tylan, and Terramycin for their eyes. I have 13 babies left, ranging from 4-6weeks approximately. 3 have been quarantined for a few days, no improvement. And woke up to a 4th with a puffy eye yesterday. I've been lucky over the last 6 or so years I guess, because I've never dealt with sick chicks before. What could be going on here???