In the egg-laying industry, once hens enter the laying period, they have to cope with all kinds of external stress every day and put all the feed they consume each day to work producing eggs. This long-term, full-capacity production workload is bound to weaken the hens’ physical condition, and their reproductive systems are especially susceptible to disease.
Another factor is the chicken’s particular physiological structure: harmful bacteria in the intestinal tract can easily reach the oviduct, causing illness in laying hens and leading to inflammation of the oviduct. The follicles may not pass smoothly and completely into the infundibulum, thereby causing yolk peritonitis.
In production, yolk peritonitis in laying hens often causes scattered deaths and culling, along with a slight decline in egg production. If it is also accompanied by infection with other viral diseases, losses in the flock can increase, resulting in significant farming losses. Therefore, this situation should be avoided as much as possible in layer farming.
Many farmers are concerned about how the disease develops and often ask about its causes. In fact, yolk peritonitis has many causes, including viral diseases such as influenza, infectious bronchitis, infectious anemia, infectious laryngotracheitis, atypical Newcastle disease, and infectious bursal disease. These and other diseases can cause congestion and bleeding in the follicles, rupture of the follicular membrane, and eventually liquefaction of the follicles.
It can also be caused by many harmful bacteria, such as Salmonella, Pasteurella, and Mycoplasma in chickens, which can also cause follicular lesions. In addition, some febrile diseases and stress factors, such as vaccine injections, can cause yolk peritonitis in laying hens.
[Clinical Signs]
Some chickens have shrunken combs and are lethargic, with their heads drawn in and eyes closed. Their abdomens are swollen and feel heavy and pendulous, and their skin is bluish-purple. The feathers behind the vent are soiled with yellow or yellowish-green feces. Egg production declines, and egg quality deteriorates, with misshapen eggs and rough-shelled eggs; some chickens may die.
【Postmortem Findings】
The livers of dead chickens show mild swelling and reddening, and the spleens show mild redness and swelling. Large amounts of yolk or yellow inflammatory exudate are present in the abdominal cavity, and the mesentery is adhered. Sometimes yolk clots of various sizes can be seen, some as large as a fist. The kidneys are red and swollen.
【Diagnosis and Treatment】
Based on clinical diagnosis and postmortem analysis, the causes of peritonitis are generally associated with viral or bacterial infection, immunosuppression, and stress. Common treatments include enrofloxacin plus cephalosporin, or doxycycline plus colistin sulfate/apramycin sulfate. In addition, Shuangxiang Fuzheng Jiedu Oral Liquid and Jiemi Huganbao are used in combination to alleviate immunosuppression and inflammation in the liver and kidneys. This treatment method often achieves good clinical results.