Is my chicken sick or molting?

[PVILLAGO]

My black star has recently dropped alot of feathers off her butt.
I checked her for injuries such as pecking abrasions but they look like they just fell out. She has lost feathers from her neck to hiney only on her underside. She has red places that appear as if burned but not bloody? I will put blue kote on tonight to make sure none of the girls want to pick her hiney. We are in Texas and it's hot. They have two pools. One in their run and one outside near their dust bath. All canopied and shaded. We give them ice in their pools daily. Frozen fruit or veggies daily. They have a commercial fan in their coop. Could this be heat related?? They are 2yrs old. No roosters. Free range during the day. Thoughts? Game camera in run??

 

[DLA]

We had a spell of really hot weather here in PA and I've got one who started molting now. If you have ruled out mites or lice and can see new pin feathers starting to come in within a few days to a week then it's probably just a molt. Increased protein for that chicken to help thru molt quickly wouldn't hurt but I wouldn't overdo it. Blue kote is a good idea for any red areas.