I have a nice small flock of a variety in my birds... There is some young and some a bit older.. I need more eggs .. so i bought 6 ready to lay of a guy... I put them in with my flock at night.. Every one got along fine..I notice that one or more of his were sneezing.. there is nothing else that i can see .. just sneezing.. .. I knew that was going to go through my flock... Now my question is.. Most of them are sneezing here and there and i can hear the odd gurgle going on in one of my rooster.. I dont want to use any antibiotics as i sell my eggs... So i was thinking that i would have to cull everyone and start over .. or can i get more birds from the same guy as i have it going through my flock anyways .. and be resistance to it ... or what would you do.