I have a hen that is very sick. She is still going outside and staying with the flock in the run, but she won't eat treats when they are given to them. One of her eyes is swollen shut and both nostrils are clogged. She is breathing with her mouth open. I am treating the whole flock with Duramycin-10 in the water. Everyone besides her look fine...no symptoms, but I am treating all just in case. I think she is going to need more help. I don't have a place to isolate her from the rest of the flock...the normal hospital is currently home to a new puppy. So, is there an antibiotic shot available that I could give her? What is it called? Do I get it at the local feed store? I am ok with giving shots since one of my dogs is diabetic. Any advice would be appreciated!