I live in an area that used to be swampland here in South Florida. There is little you can do to eliminate mosquitoes without spraying tons of insecticide around, which I think is worse than the bugs. I try to reduce the number of things that collect standing rain water, but there are mosquitoes who can breed in a cupped leaf. Every summer I have chickens affected by fowl pox, but it is always the new young birds. The older ones already have immunity, even though I see mosquitoes swarming around them as they roost.
I rarely treat the lesions, and have rarely had any problems with the affected birds. They usually get better all on their own. It does bear watching, to make sure it isn't affecting their eyes or nostrils. Only once did I have birds get the wet form of the pox and die. And this year I had a tiny Dutch bantam roo get some lesions on the very end points of his comb and it seems to have caused them to fall off. Or maybe they got pecked off because they were already raw.
So if you have some rare & valuable birds, or special show birds, you may want to take more protective measures & more radical intervention. You can even vaccinate the birds against this. Otherwise, just watch & monitor to insure it doesn't affect their soft moist tissues, watch for infection, and wait for it to run its course.
Some folks here use black liquid shoe polish to cover the lesions. The waxy liquid seems to help them dry up & fall off.
