It would be overkill to use a systemic antibiotic at all, IMO. If you keep an antibiotic ointment or cream for your family, just use that, or pick up a tube of Neosporin at the drug store. The only precaution with topicals is, do not use one with a "caine" drug in it such as cetacaine, benzocaine, etc. You could also dab them with Betadine or BluKote (gentian violet.) Or, do nothing.
When mine had it, the only lesions that concerned me were those near they eye, so I used Neosporin on them, once, because you can actually use the brand name Neosporin ointment as an eye ointment. Or you could use Terramycin ophthalmic ointment from the feed store. When it showed up on a couple of new birds the next year, I did nothing, with no problem.
Having dry fowl pox works like a vaccination in itself; each bird will be immune to it after the lesions go away, which will take about 3 weeks. You will likely simply find one day that they have suddenly disappeared. I've read of people giving the vaccination after the infection, supposedly to lessen the severity, but this makes little sense to me since there is nothing severe about they dry form in the first place.
