Bare spots showing up on nearly all my chickens.

[Excogitate]

This pic is of my EE. But my RR has it on back of her neck and another has it below neck on breast. Everyone seems to be happy and healthy otherwise.

Thoughts? Mites/lice?

 

[Hishigata]

It could be mites or lice. They tend to congregate and lay eggs at the base of the feathers so check there first. It could also be a bully hen pulling feathers to put the other hens in their place. Keep an eye out for any aggressive behaviour. Otherwise, if you have a rooster they can also cause bald spots on hens they particularly favour.