It's probably safe to eat just about any chicken with most common diseases, however, unless I was just really starving and desperate for food, I would skip it myself. That's just me. I mean, it's only a couple of birds. Whole chickens are not that expensive and what difference in your grocery...
Honestly, though I do not buy birds, not even folks I trust and who I believe to have disease-free flocks, if I did and was in this situation, after all this happening with them, I can only tell you what I would do. I'd cull the rest of them, disinfect everything in sight, heavily lime any...
Medicated feed does nothing for an adult bird and not much for a chick-it's supposed to help only with coccidiosis, but really doesn't much.
I'd leave them in quarantine for at least 6-8 weeks, considering what you've already had happen to them. In your rooster, you'd look for discharge from...