Missing neck feathers, red skin

[chx3to10]

My hen is missing neck feathers and has rough red skin, I had another chicken do this, that one had a poopy bottom, pampered treatment cleared her up and feathers grew background on her neck, then she got sick again and was no turning around the second time, stopped laying eggs, eventually bloody stool and then wouldn't eat. Two weeks after she was gone my barred rock began the same losing neck feathers but no sign of other symptoms. Should I be concerned?

 

[Lewis Farms]

How is she doing? I have no idea what it could be but very curious. Did you send the other girl to a vet school or a vet for a necropsy?

 

[chx3to10]

As it turns out, the fence in the photo-they stick their heads through it to eat the greener grass on the other side. Being chickens as they are, they spook at anything and everything, and rip their heads back through the fence, usually while their chin is down eating-resulting in the feathers being ripped out/off. Silly birds.