Help! Red chest and loss of feathers

[madchickendad]

Hi can anyone help identify what's happening to my female 'Mavis' she's suddenly losing feather on her chest and stomach (for want of a better word), and the skin's going red. Photo of her chest to show the problem. It's pretty cool here so I'm thinking it shouldn't be mites. She's eating well and laying well but I'd like to help her as soon as I can. All help appreciated! She's my lead hen out of the two and there doesn't seem any infighting/hen pecking going on.

 

[Chookiemom]

Do you think she may be going broody?