bald heads

Has anyone solved the problem of hens going bald on their head? I've seen losts of comments on various sites and all anyone has said so far is it's caused by one bullying the others or mites or by the cockerel. Mine haven't got mites, I don't have a cockerel and can't see any of them bullying the others. Their heads aren't sore just bald. I'm sure it's not boredom as they free range in a very large garden. I did see one blog that said it always seems to be pet hens that suffer. One person said that it happens to his during summer but it's happened to mine in the coldest part of winter.

Hi there. I don't have a solution but 1 hen I had went bald on her head and then in a line down the underside of her crop and then underneath. She was about a year and half old when it happened and never regrew the feathers though she seemed quite happy in all other respects.

I have often wondered if it could be a fungal problem.