I treated them with iodine, but mostly just let it run its course. My Cream Legbar hen had a big pox on one of her nostrils that seemed to be blocking it, but the other side was open. I looked in her mouth and it didn't seem to be affecting her mouth or throat significantly. I did put some iodine in their water, in addition to putting it on the sores. Their feet are looking much better now.
I decided against vaccinating the rest of the flock there. It definitely seems like it hit birds harder depending on the state of their immune system. Apparently the birds at the farm where I have my breeders had pox a couple of years ago. This current outbreak started with a cockerel who was lowest on the pecking order and spent too long hiding his head in a cinderblock, and thus not eating or exercising. By the time I got him isolated from the bullies (i.e., his brothers) he could hardly stand. And that's when he got the pox. (BTW, giving him food and water that he could reach and isolating him, as well as taking away his cinderblock, was enough to get his strength back and get him through the pox). Right next to that coop were my CLs, and they came down with it, too.