I went and looked at molting, and yes that is probably what is going on with her. This is my first year with chickens, and this one came with the coop, my others are still babies. Losing one this week has me freaked out and I have looked up so much information, kind of like looking at WebMD...
This one here is 7 years old. I did have one pass yesterday, but she was only 6 months old, her feathers were fine, they didn't look like the older hens.
Thank you all for your post. We are brand new to chickens (just a few weeks) and found the same thing with an older hen that came with our coop. If I am understanding correctly we need to give her some oyster shells to help with this issue? She has giving us about 4 eggs in the last two weeks...