The condition usually exists in various stages within the entire population of birds. The breast bone will lack any muscle covering and seems to be covered only by a layer of skin. The name of the condition is Ulcerative Enteritis, or Quail Disease. The disease is caused by a bacterial infection in the small intestine of the bird.
Ulcers appear and reduce the amount of nutrients that the intestine can absorb.
The lack of nutrients causes the extreme weight loss and muscle deterioration. More information on this disease is available in the Diseases of Poultry publication. It is generally recommended that a preventative drug like bacitracin or penicillin be included in the feed to reduce the incidence of outbreaks. Use of a coccidiostat like monensin has also shown to be beneficial. Many strains of the disease causing bacteria have been isolated and some strains have shown high resistance to the more beneficial drugs we use.