Chickens often die right after the cold weather wanes and the weather gets warmer. This is most often the result of upper respiratory fungal infection. When conditions are damp, mold begins to form in the chicken coops and when the mold dries, the bacteria develop spores and find a place where they can survive.
Sadly, often times the spores are inhaled by the chickens, landing in the lungs and the trachea of the bird. This area of the body provides the spores with a warm and moist environment in which they can grow. The upper respiratory fungal infection is thus created and quick to kill.
This infection is something most grown stronger chickens can handle, but not the young, the weak and the old. This disease can stay in latent form and erupt when the chicken is under stress. When infected, they often make gurgling sounds, sneeze, and stretch out their necks, while coughing and wheezing. There is a medication called “Oxine” that can help your chickens fully recover.