What does this sound like?

On Sunday I had a two year old Isa Brown hen die. She didn't look well the night before - pale comb, fluffed up and hunched over. She went outside with the others in the morning and at about 2 in the afternoon I found her dead in the corner of the coop. She had looked a bit "depressed" a few times through the winter, but kept on doing her chicken things.

Just now I went out to check on everyone and found one of my nearly 7 week old chicks flopping around on the floor. It's like she's lost strength in her legs. I am really worried now because these chicks have been in the other half of the coop as the hens separated by a wire door for about two weeks now. Is there anything I can do to keep this from spreading?

My experience of losing a two year old ISA is not that unusual. Usually they die of egg peritonitis or calcium deficiency. The fact you have a young chick, not well, in close proximity, is a concern but could also, if you're lucky, just be a coincidence. Hopefully, others will have more experienced input to your situation.