Clinical signs and gross lesions
Young chickens, 2 to 5 weeks of age, with vitamin D3 deficiency are unable to stand and have very soft, pliable, legs and beaks. The rib joints are swollen like beads and curved inward. The breastbone often twisted.
In laying birds, vitamin D3 deficiency causes soft-shelled eggs and a drop in production
Treatment and control
Vitamin D3 can be given as treatment, usually in combination with calcium and phosphorus.