Don't just jump out and sell off.... just do research, and figure out what you are doing wrong. I am not trying to insult you in any way, shape, or form... but when you have young, previously healthy snakes dying and getting respiratory infections, odds are it isn't bad luck but something you are doing wrong.
Don't know if there are any other threads on this but would you care to describe your set up and all your practices and procedures so we can help you trouble shoot?