Hello, I've learned the hard way to quarantine before exposing new chicks to the rest of your flock. History: All as well before I introduced new chicks to an existing flock. Started having respiratory issues and some have died due to that. My dog killed a few (lesson learned there as well) and they have had clear/tan mites which I treated them for 2 weeks ago. After the mite treatment, I felt everything was better as the chickens seemed more relaxed and weren't pecking at their skin. Current: Today I noticed a chick was losing some feathers around her neck. I started inspecting her and she seems to have white scabs all over here skin.... see pictures. Additionally, she is having trouble breathing (raspy breathing) and when I flipped her over on her back she started gulping for air. I'm thinking about culling her, and will probably have to do so for the rest of the flock but wanted to check here first. Any ideas whats going on? Here are the images: http://imgur.com/a/UlvJY Thanks!