The topic is interesting but I note that several people have mentioned medication and, in particular antibiotics. Medications should only be used when absolutely necessary, a treatment for canker, worms or whatever. Supplements are something completely different of course and most fanciers will use these although they might not class them as supplements. For example glucose, oils, iodine , iron the list is endless. Any fancier who wins out of turn without any medication or supplements of any kind has the birds we all need.