I haven't used fowl pox vaccine, but I have been looking at it recently. I think it requires 2 times for full immunity, and is given on the wing with a 4-pronged tool. Fowl pox can last several weeks, maybe over a month. Those that have it will be immune and not spread it when recovered. Here...
If it is fowl pox, it doesn't require antibiotics unless there are yellow lesions inside the mouth and throat.That is wet fowl pox. Dry fowl pox is a virus carried by mosquitoes, which will spred among your flock. Wet fowl pox is also the same virus, is very serious and can be fatal.