My chickens had pox. Looked really reallly bad, like your photo. The bumps got bigger and bigger, deforming the faces of the ones with it the worst.
I started euthenizing the worst ones. Lovely big brahma hen, my favorite.
then got on BYC forum at the library and found out it was pox. And that they'll recover completely from it. And they did. The horrible bumps went away completely and their skin smoothed back out. No scarring or pitting. All good again after about two or three weeks, can't remember exactly how long it took to go away.
It is not just little spots like chicken pox on children.
Summertime. Spread by mosquitos.
I had never heard of it before and thought it was a terrible form of cancer.
Especially on their faces and EYELIDS!!!! The bumps are multi colored, a lot of dark color too to them.
Tell Newbies about it. I wish it was a photo banner across this forum - so that I knew about before I started euthanizing the birds.
I can't tell for sure from your pic. A pic of the faces and eyelids would help.