This project was designed to determine the incidence of various leg disorders in commercial broiler chickens and to elucidate the effects of leg deformity on the metabolism of broiler chickens in terms of serum levels of calcium, phosphorus, sodium, potassium, chloride and also on the morphology of liver, kidneys and pancreas. Fifty leg deformed broiler chickens were collected from 38 different commercial poultry farms in and around Lahore, kasur, Sialkot and Gujranwala Districts.

Out of the observed cases of leg deformity, 18 cases of valgus, 13 cases of slipped gastrocnemius tendon, 9 cases of curly toe, 5 cases of femoral head necrosis, 3 cases of varus and only 2 cases of synovitis were reported. This data of incidence of various leg deformaties were analysed on the basis of age, sex, strain of bird and also on the basis of location of deformity. It was noted that the most frequently encountered leg deformity was valgus. The maximum incidence of valgus occurred at 5th week of age. The males have greater incidence of valgus as compared to females. Hubbard strain had greater incidence of valgus in comparison to other strains of birds.

Unilateral cases of valgus were more common than bilateral. The levels of all minerals were decreased in experimental birds as compared to control ones. The mineral levels of birds affected with valgus deformity showed that there was a highly significant difference in the levels of calcium phosphorus and sodium between the experimental and control groups. But there was a non-significant difference in the levels of potassium and chloride in both the groups. The slipped gastrocnemius tendon was noted frequently at 7th week of age, slightly more in females and all the reported cases were unilateral. Hubbard strain was found to be most liable to slipped tendon. The mineral levels of birds affected with slipped tendon showed a highly significant difference in the levels of calcium, phosphorus and potassium between the experimental and control groups. A significant difference was also noted between the experimental and control groups in terms of levels of chloride, but a non-significant difference was recorded between the experimental and control groups in case of serum sodium level. Curly toe was again recorded to its peak in birds of 7 week age, more in males and mostly bilateral. Hubbard strain was found to be the most affected one. The mineral levels of birds affected with curly toe showed a highly significant difference in the levels of calcium and phosphorus between the experimental and control groups. But a non-significant difference was noted between the two groups in cases of serum levels of sodium, chloride, and potassium. Femoral head necrosis was recorded at its highest incidence at 9th week of age, more in males, and all the recorded cases were unilateral. The strain most liable to femoral head necrosis was Indian river. The mineral levels of birds affected with femoral head necrosis showed a highly significant difference in the levels of phosphorus and potassium between experimental and control groups. A significant difference was also recorded between the experimental and control groups in terms of levels of calcium. But in the serum levels of sodium and chloride a non-significant difference was obtained between the two groups. Varus was recorded more frequently at 6 and 7 week of age, more in females, and mostly unilaterally although bilateral cases were also noted. Hubbard, Arboracres, and Lohmann strains showed more susceptible behaviour. The mineral levels of birds affected with varus showed a highly significant difference in the level of calcium. A significant difference was also recorded between the experimental and control groups in terms of levels of phosphorus and potassium, but a non-significant difference was noted in the sodium level between the two groups. Synovitis was noted mostly between 3 and 6 week of age, more or less equally between males and females. Both unilateral and bilateral cases were seen, and Hubbard and Arboracres strains were found to be more prone to synovitis. The mineral levels of birds affected with synovitis showed a significant difference in the levels of calcium and sodium in the experimental and control groups. But a non-significant difference lies between the two groups.

In all these various types of leg deformities, the macroscopic lesions like, slight enlargement of liver along with discolorization and necrotic areas and in some cases congested livers showing the lesions of perihepatitis were also noticed. The kidneys showed inflammatory signs alongwith urates deposits. A pale fibrosed pancreas showed atrophic changes. The pancreas was the most severely affected organ. In majority of the birds it was severely atrophied presenting a shrunken fibrous band like structure in the convoluted duodenal loop. The colour of these pancreases was white or off-white to pink and were firm in consistency. Microscopically cloudy swellings and severe necrosis were seen in the affected livers. Mononuclear and plasma cell infiltration were also quite evident. Leukocytic infiltration in the interstitial spaces and glomerular region were quite evident. The dilated blood vessels and haemorrhages in tissue spaces were observed. In some of the severely affected cases the glomeruli were enlarged and were less in number as compared to that of normal birds.Lesions of necrosis were also noted in some of the affected kidneys. Pancreas was observed that the acinar cells were atrophied and underwent vacuolation, degeneration and necrosis. The Zymogen granules were almost absent from acinar cells. Heterophil, leukocytic and lymphocytic infiltration were frequently encountered in affected cases. A characteristic change was an inflammatory reaction in one or more pancreatic ducts where the epithelium and fibrous tissues occluded the lumen of the ducts and led to obstruction in pancreatic drainage.