I have thought on this too, I think it is best to treat for a specific problem if it crops up, as if you over medicated or medicate when not needed ,could just make the illnesses stronger if it strikes as it can get immune, I think it is best to build your birds natrual immune system by having healthy practices and good feed. and treat as needed. now for breeders, I think they should be medicated for canker before breeding. JMOwhat are everyone's thoughts on the 4 in 1 treatments loft wide as a preventative measure? i'm not having any problems in the loft right now but traditionally this is the time of year i start to see them so i thought it may pay off. thoughts?