Most sick chickens take to isolation crate well as they aren't feeling great. Remove these two affected immediately to contain the exposure (although they've already exposed the flock...but you can prevent more exposure in case it is something bacterial, that moves slower in most cases).
Put the birds in a dog crate (whatever) that is in a weather protected environment will help. Place any antibiotics in that water.
It may be MG which is responsive to tetracyline. Coryza responds to Sulmet.
Fowl Pox has to run its course as it is viral, ETA as does Infectious Bronchitis. You can help boost the immune system with ACV, yogurt, warm mash with garlic. I've even helped a bout of IB by putting elderberry tincture in the water. That seems to help with viral stuff for chickens as it does people.
Edited by Lady of McCamley - 1/7/16 at 9:01pm