Scoliosis developed in 55 per cent of sexually mature birds (68 per cent
of male and 46 per cent of female birds) in a highly inbred line of
chickens originally produced from white Leghorns. The curve could first be
detected at five to six weeks of age and progressed until spontaneous
fusion of the thoracic vertebrae occurred. Studies of these chickens
indicated that abnormalities of growth and development of the spine are not
the primary cause of the scoliosis. Preliminary studies of the
paravertebral musculature also indicated that simple muscle imbalance is
not responsible for the curve. Initial studies of collagen extracted from
the scoliotic line of chickens showed it to be more soluble than similar
collagen extracted from white Leghorn controls.