Found a dead hen on Sunday. Then another, young rooster, died in front of me (separated from the flock), bleeding through the nose or beek. I put them on Duramycin yesterday. So far no more deaths, but two chickens bleeded on the roost at night, I found blood on the roosts. They are both hardly walking, just sitting around looking sick. Their heads turned sort of greenish color. Is this some kind of respiratory disease? Will Duramycin take care of it or need I do something else? Thanks!