On July 22, 1992, two one-year old female White Pekin ducks were presented to the College of Veterinary Medicine - Cornell University with a chief complaint of lameness. Both ducks had a history of being heavy layers and were being fed a commercial duck grower diet containing 0.6% calcium (requirement at least 2.75%). They had been treated with baby aspirin, Baytril, and dicalcium phosphate supplementation to the feed with no clinical improvement. Duck 1 was partially weight bearing on the right leg. A fracture was palpated in the right femur and a bumblefoot nodule was noted on the plantar surface of the left foot. Duck 2 lay in sternal recumbancy. Fractures were palpated in both the left and right femurs. Based on the history and physical exam, a working diagnosis of nutritional secondary hyperparathyroidism (NSH) was made. This paper will address pathophysiology and clinical findings of this disease as well as approach to treatment in this case. In additon, pecularities of avian bone will be mentioned.