Denagard, from what I have read about it, is kind of the "last resort drug" when your chickens have been sick before and are not responding to more common drugs like tetracycline, tylosin (Tylan,) and erythromycin. It is expensive, hard to find, tastes very bitter, and some have to doctor up their water or put it in food before the sick birds will take it. Since you have never had sick birds before, I might be conservative and treat with the more common ones like Tylan, and leave the strongest one for later since your chickens may need it later. So far, it apparently has no resistance. It would be good to be able to use it as a preventative, though. Eventually all drugs meet resistant diseases.
