1. Tendon-removing disease: The etiology of tendon-removing disease is rather confusing, and the lack or absence of manganese, choline, nicotinic acid, folic acid, biotin and nicotinic acid in diet may cause this disease. The development of epiphyseal growth plate was blocked, tibia was shortened and twisted, cartilage was malnourished, epiphyseal end of trunk was thickened, epiphyseal joint was swollen, distal tibia and proximal tarsal bone were twisted outward, and intestinal tendon was dislocated, resulting in outward bending of legs and deformation of legs and feet. Sick chickens can't stand, but move on the ground by tarsal joints, and die because of difficulty in drinking water.
2. Tibial chondrodysplasia: The incidence of this disease is related to the ion balance in chickens. When a large dose of phosphorus, chlorine or sulfur is supplemented in feeding speculation, the anion level increases and the incidence of this disease increases, while when calcium, sodium, potassium and magnesium are supplemented, the cation level increases and the incidence of this disease decreases. Osteochondrodysplasia of tibia is caused by abnormalities of proximal tibia, tarsometatarsal bone and distal femur. The tarsal joints of sick chickens are swollen and they walk unsteadily. In severe cases, it cannot stand and walk. Because the uncalcified and vascularized cartilage extends from the growth plate to the main energy end, white and transparent "cartilage plug" can be seen on the section, and its shape and size depend on the disease.
3. Leg deformation: The cause of this disease is still unclear, and it has been reported that it may be related to the contents of amino acids and tannins in feeding guesses. Leg distortion includes varus and valgus, varus is an arched leg in which the tarsal joint bends outward, and valgus is an arch leg in which the tarsal joint bends inward and leans together. The distortion of the calf is caused by the twists and turns between the proximal tibia and the distal tarsal bone, but the long bone of the sick chicken grows normally and the epiphyseal growth plate develops well.
4. Rickets: This disease is caused by vitamin D3 or calcium and phosphorus deficiency or imbalance between them. Sick chickens are characterized by leg weakness, unsteady gait, limping and frequent squatting. In severe cases, people can't afford to lie on their side or lie prone, and their legs are splayed. Some joints are swollen, bones are deformed, bones are soft and easy to bend, and epiphyseal growth plates are widened. The mouth becomes as soft as a "rubber beak", the keel is deformed into an S-shape, and the joint between the ribs and the spine is beaded and spindle-shaped.
5. Leg weakness caused by vitamin deficiency:
(1) Vitamin B 1 Deficiency: chicken legs are weak, walking unsteadily, toes are bent inward, in the initial stage, walking with head raised and feet lifted, and moving on the ground with tarsal joints. In severe cases, the legs are numb or paralyzed, and they can't afford to lie on the ground, and their legs are straight, showing a typical "star-watching" posture. (2) Vitamin B2 deficiency: When sick chickens walk or walk with their tarsal joints on the ground, they often spread their wings to maintain balance, the joints swell and deform, and there are proliferative connective tissue lumps around them, and their toes bend inward to form a semi-fist. In severe cases, you will lie on the ground with your legs apart, or one leg will be forward and the other leg will be backward. Autopsy showed that there was yellowish mucus in the tarsal joint cavity, hyperplastic connective tissue in the joint space, and bilateral sciatic nerves were 3-5 times larger than normal.
(3) Vitamin E deficiency: Vitamin E deficiency is similar to selenium deficiency. It was difficult to walk in the early stage, and the station was unstable. Late leg numbness, lateral lying, leg extension, leg twitching. Sometimes these symptoms will break out intermittently. Chickens with this symptom died quickly.
6. Weak legs due to zinc deficiency: caused by insufficient effective zinc content in the feeding conjecture. Sick drumsticks have weakness, dyskinesia, short and thick long bones, swollen tarsal joints, flaky skin on legs and feet, and necrotizing dermatitis in severe cases.