I bought a rooster with a pretty nasty respiratory infection. The previous owner was a small time farmer but did have documentation for a clean flock. I already love this little Roo. We've had some nasty weather which doesn't help this situation. A week prior to buying the Roo one of my other hens got a respiratory infection as well. Then an hour after the new Roo another Roo started sneezing. The new Roo has yellow mucus stuck in his nostrils. He had a good apetite however and seems otherwise fine I have Penicillin here at home. I plan to go to Tractor Supply for heat lamps in a few minutes and I need to know dosages to know what size syrenges and needles to get. I've never done chicken injections either. I'd rather not buy a whole new bottle of antibiotic unless it's cheap. So my question is, how do I treat an respiratory infection? I have Penicillin and need to know the dosage and needle size. Any and all help would be wonderful.