I have what I would consider a large flock of personal chickies, about 50 of them and had all my chickens vacinated for it. Wel the ones that came from the hatcheries, but wasn't sure of weather or not it would be a good idea to have the keets vacinated too, and though they say that the hatchery (ideal) does not recomend it for chicks or other fowl for a small backyard flocks it does give the option for the mereks shot. I will do some more investigating on the subject also, but really thinking I might go ahead and get it just to be on the safe side and protect everybody.?? Just wasn't sure if they could get it or if they could be carriers, I don't want to take any chances with my girls. Thankyou for the responses.