lethergy

I have a 2yr old Red Hybrid type of chicken. She stopped laying a couple months ago. Her last egg was a giant egg with no yolk. She has lost a lot of weight so her breast bone is protruding otherwise. I’ve noticed her looking a bit off a few days ago, a bit scruffy but acting normally...

Returned from vacation on Sunday evening. Had our neighbor watching coop as she has done before. She called Sunday morning letting me know that she had found one of the chickens dead and another hiding under coop and wouldn't come out. No other concerns. Got home, found chicken still under coop...