Prolapse in laying chickens is a common problem that can be very distressing and potentially fatal if not treated. So what is a prolapse in a chicken? The average chicken lays about 300 to 325 eggs per year. Once hens reach reproductive age, most will lay an egg almost every day usually without any complications.
During the process of laying an egg, known as oviposition, the shell gland (the lower part of the hen’s reproductive tract where the egg shell is formed) is temporarily turned inside out or everted along with the egg. This allows the hen to lay a very clean egg. On occasions the oviduct will not retract immediately once the egg has been laid. This condition is known as prolapse. If not noticed immediately, other birds will pick at the protruding material, often causing haemorrhage, infection, infestations of maggots and death if quick action is not taken.
There are several causes of prolapse in chickens, these include: being over or underweight, unbalanced feeding, the reproductive age of the chicken, excessive size of eggs (often laying a double yolk) and early photostimulation. This is where increased day length is used to stimulate sexual maturity. Birds that are exposed to increasing day length before their reproductive tract has fully matured are more likely to suffer a prolapse. This is because the reproductive tract may not be fully matured when they begin lay.
The management and care of laying hens during the rearing and laying period can play a significant role in prolapse problems. One of the main causes of prolapse is being overweight. Hens that are overweight are more prone to prolapse due to general muscle weakness and a tendency to lay larger eggs. Too much fat around the reproductive organs can also lead to prolapse.
Birds that are underweight when the birds begin lay are more likely to suffer prolapse because they may begin laying before the reproductive tract has completely matured causing damage.
Another main cause of prolapse is insufficient calcium in the diet. This will cause problems with eggshell formation but can also result in poor muscle tone. Poor muscle tone may cause problems with oviduct retraction once the egg has been laid. The longer the oviduct remains outside the body, the greater the chance other birds will peck at the protruding prolapse, which causes immense distress to the chicken and can be fatal.
One of the first signs of a prolapse problem is the presence of blood-streaked eggs. As always, careful and vigilant management will lower the rate of prolapse as well as most other chicken health problems. If possible, isolate the affected hen to prevent further damage and attack from other hens.
One way to avoid a prolapse in chickens is to ensure a balanced diet. Incorrect feeding can not only cause overweight hens, but egg bound chickens too that are prone to prolapse. Feed rations are required to sustain egg production and maintain body weight at recommended levels. Consult with a feed provider if you are not certain.
Ensure that the light intensity in the hen house or coop is at the breeder recommended level. Consider reducing the light intensity by covering windows, or replacing bulbs with lower wattage bulbs. If your chickens are laying a lot (more than 4%) double-yolked eggs, gently restrict feed intake by about 5-10%.
Spend time with your birds to observe vent-pecking behaviour, and isolate them from the flock.
Treatment of a prolapse is never pleasant. The protrusion can be guided back inside with gentle pressure and suitable lubrication, but this can be a skilled job and better undertaken by a trained professional. Once having treated the prolapse is no guarantee of a solution as the condition will often reoccur as soon as the chicken is let go or when it next tries to lay an egg. A vet may be able to temporary suture the hen to hold the prolapse in place until the swelling goes down. This however can cause problems with defaecation and egg laying, so great care needs to be taken if this method is adopted. Steps to reduce the laying capabilities of the hen can aid her recovery. This can be done by switching her feed to a diet rich in corn.