Correct wormers, at the correct dose. Most info on the web is telling people to give too little. Or they think they're being clever by assuming that the goat or cattle dose of something is what chickens should get, which is not true in most cases.
All wormer doses can be found here:
http://avianmedicine.net/content/uploads/2013/03/18.pdf
http://avianmedicine.net/content/uploads/2013/03/09_therapeutic_agents.pdf
and books like Plumb's Vet Drug Handbook and Vererinary Parasitologly Reference Manual. Compare all, find the most common, rule out the highs and the lows and bingo, there is your dose.
-Kathy
i was more talking about the mammals and worming
my horse had tape worms, vet told me to use Quest
OMG the people telling me not to use it because it killed a horse
little did they know and not do their fact checking, some idiot OD'd her Mini