Hey guys, I'm stumped. No new birds previous to the first death, no visitors, no trips to chicken places, nothing. Full biosecurity measures. Enclosed coop, covered run, whole nine yards. Ages varying from 14-18 weeks. Enter the nor'easter. Chicken door to the coop slams shut in the wind while I'm at work, trapping one girl in the coop away from food and water. Found dead later that night when I got home from work. Resolved to fix door, thought nothing of it. I did examine the body - clean vent, no crusties around eyes or nostrils, no obvious signs of sickness. This was Wednesday night. Went to check on girls the following morning and the human door caught in the wind and it ripped it right off the coop. Evacuated girls into an enclosed area of the workshop, where they stayed happily for 4 days while I waited for the weather to clear and repaired the coop. Also cleaned out the coop and laid fresh bedding down. I put the girls back in the run yesterday afternoon. After they returned to their coop, I went and picked up a replacement bird for the one I had lost (presumably to dehydration/heat stroke) and put her in a quarantine in the workshop (yesterday, so Sunday). Zero interaction between new bird and existing flock, and a distance of over 25 feet between birds at all times. All of my outdoor birds went to bed on schedule. This morning, four of my five remaining outdoor girls come out into the run when I let them out. I normally call to them before I open the run so I don't scare them and get chattering in return. No chattering this morning. I go searching for #5. She's in the coop, on the floor in the litter as if she's made herself a nice little nest. Eyes open and clear, not struggling to breathe, no facial swelling, feathers not ruffled, just looking very sleepy and lethargic. Non-responsive to me dangling things near her head (she'd normally run). I did a visual check only on the quarantined bird afterwords, barely sticking my head in the room as I was starting to get spooked at this point. I had to go to work, so had my mom come over and bring the ailing bird her inside, blow her off with a hair drier and get her warm and comfy. Declined meal worms, declined food of any kind. Died a few hours later. Now, this bird was playing hide and seek with me in the workshop yesterday when I was moving them from the shop to the coop - she snuck out and was running all underneath the benches giving me a hard time - hale and healthy bird, no signs of respiratory distress even with all the action. 16 hours later: dead. I've already reported the losses to the USDA who are coming to collect the body and swab my remaining birds, and I will be re-checking all birds for mites when I get home. No bloody poops anywhere, no overt signs of sickness. Picking up some Corrid to treat their water on the off chance it's coccidosis, which I really thought they were too old for, especially with the biosecurity measures I have, but I don't know what else to do at this point. All I have is lethargy and a rapid death. I'm completely stumped. My other birds appear fine, but so did this one 16 hours ago, and frankly, I'm terrified.