Winter often triggers various diseases, so caution is essential, especially regarding the following two chicken diseases.
One. Osteomalacia
During chickens’ growth and development, especially in winter, if the metabolism of minerals in the body—particularly calcium and phosphorus—is disrupted, abnormal growth of bone tissue may result, leading to a nutritional disease. In adult chickens, it is usually called osteomalacia; in chicks, it is usually called rickets.
(I) Symptoms
Affected chickens mainly show poor growth, loss of appetite, ruffled feathers, and soft, curved bones. Round, bead-like hard swellings form where the soft and hard ribs meet; the chest is flat and flattened, protruding on both sides. In severe cases, the beak is soft like rubber, making it difficult to peck at food; both legs are painful and unable to support the bird, and most birds lie down. The shanks of chicks curve into an arc or an X shape, the spine curves, and their calls are weak. The laying rate of hens declines.
(II) Preventive measures
1. Provide chickens with sufficient calcium, phosphorus, and vitamin D; it is best to feed them a complete compound feed.
2. Provide 16 hours of light each day. Also provide grit to improve the chickens’ digestion of feed.
3. Provide some green fodder in appropriate amounts.
(Three) Treatment methods
1. When sick chickens are found, promptly increase the proportion of calcium and phosphorus in the diet. Generally, the calcium and phosphorus content in the diet is: chicks 0.9%, growing chickens 1.1%, laying hens 3.1%–3.5%, and meat chickens approximately 0.9%. The calcium-to-phosphorus ratio is: chicks 2，1:1, growing chickens 2.3:1, and laying chickens 1.7:1. Pay particular attention to supplementing vitamin D or cod liver oil to promote calcium and phosphorus absorption by the chickens. Generally, add 2000 international units of vitamin D per kilogram of feed; give each chicken 1–2 milliliters of cod liver oil per day.
2. Add substances such as bone meal to the diet. Bone meal can account for 1%–2% of the diet.
II. Low-temperature disease
“Low-temperature disease” is a condition that tends to occur frequently during the low-temperature seasons of autumn and winter. This is especially true in northeastern China, where temperatures are low. During the laying period, hens have a relatively high demand for calcium and phosphorus. If their feed intake is insufficient, and they also have metabolic disorders involving calcium, phosphorus, and other nutrients, abnormal growth of bone tissue can result, leading to a nutritional disease. This disease is highly harmful and directly affects egg production: eggs become smaller and eggshell quality deteriorates, seriously affecting the returns from chicken farming. Therefore, during the cold season, especially in northeastern China, efforts should be made to prevent and treat “low-temperature disease.”
(I) Symptoms
Affected chickens show poor development and reduced appetite. Their bones become soft and bent, with bead-like hard nodules at the junctions of the soft and hard ribs; the chest is flattened and protrudes to both sides. In severe cases, the beak is soft like cartilage and can bend, making pecking difficult. Most adult chickens lie down and have difficulty standing.
(二) Preventive measures
1、Formulate the diet appropriately according to nutritional standards, providing the chickens with sufficient calcium, phosphorus, and vitamin D. If possible, it is best to use complete compound feed to ensure the chickens’ calcium and phosphorus requirements are met.
2、Provide sufficient light at the poultry farm. In general, 16 h of daylight per day is recommended. If daylight is insufficient, artificial lighting may be used instead. At the same time, supplement the feed with grit to improve the chickens’ digestibility of the feed.