Hello-I started a new flock mid-August this year, (from three different sources, all were healthy) but three have died from a disease that is still affecting the others (6-8 weeks later). They are wheezing, sneezing, roosters are crowing very little, if at all, no mating, some have large amounts of watery diarrhea, mucus on noses, and weak combs. Others show no signs at all, and others lost weight rapidly after 2-3 weeks and died. One rooster smells oddly as well. Not sure what to do to prevent this, I was hoping to increase the flock to about 30 in the spring, but I don't want to bring in 25 chicks and have them all die. I had chickens a year ago, and a rooster had a 'boil' from getting pecked and it erupted and killed him, along with 2-3 others. I got rid of the remaining 3 chickens, but it seems the disease lingered. Any advice would be much appreciated.