Egg Binding and Chronic Egg Laying
Dr. Jenni Bass
A chronic egg layer is a hen whose laying is prolonged, excessive or out of season for her species. Chronic egg laying is usually associated with lovebirds, cockatiels, finches, canaries, budgerigars and doves. Most avian species kept as pets, however, can exhibit unwanted reproductive activity, and eggs can be laid with or without the presence of a male. It cannot be predicted with certainty whether a given bird will or will not develop problems associated with egg laying. In the case of birds from temperate zones, it may help to increase the number of dark hours to mimic a change in season. Birds should have 11 to 12 hours of uninterrupted darkness at night, and gradually increasing this to 14, even 16 hours may help.
Egg binding is a delay in the normal passage of the egg through the oviduct (analogous to the mammal's uterus). Dystocia, meaning difficult or abnormal birth, refers to a mechanical or physical obstruction, which prevents laying. Nutrition, physical condition, genetics, health and environmental factors as well as the presence of underlying disease all play a role in egg binding, dystocia and their associated life threatening complications.
Good environmental and nutritional management can lessen the likelihood of laying and make it safer if it does occur. In the case of the hen intended for breeding, sound aviculture practices and recognition of the natural needs and limits of the bird will increase the production of healthier chicks from healthier parents. In spite of all preventive measures, problems will sometimes occur, which require medical treatment or surgery.
The Wild vs. Captivity
In the wild, natural conditions influence the biological drive to lay: The hen must bond to a mate, there must be sufficient nesting material or sites, the food supply must be increasing and the day length must be adequate for chick rearing. The relative importance of these and other factors in influencing hormonal changes varies with the species and geographical origin. When these criteria have been met and the hen has laid a genetically influenced number of eggs, incubation begins. This is followed by hatching, fledging and weaning of chicks. Depending on the species in question, this cycle may repeat within the year, or may take more than two years to complete.
In captivity there is little cyclic variation in the presence of stimuli to lay. The "mating bond" is often between bird and owner, food is always plentiful and artificial lighting leads to unnaturally long days. Birds will often find "nesting sites" outside the cage, in boxes, drawers and on bookshelves. Finches and canaries are often provided with a nest in which to sleep. Lovebirds, canaries, budgies and cockatiels among other species have been bred in captivity for many generations, and in many cases are far removed from the wild type. In selecting for birds that breed easily, we may have selected for birds that produce unnaturally large clutches.
What to Do if Your Bird Starts Laying Eggs
The point at which egg laying becomes excessive or detrimental is unpredictable and depends on the individual. The hen's genetics, her environment, her health and nutritional state will all play a role.
The hen's overall physical condition will affect her ability to lay successfully and safely, so a physical examination performed by an avian veterinarian is recommended. Blood tests or radiographs (X-rays) may be suggested in these cases to assess, among other things, blood calcium levels and bone density.
Be sure that the hen is on a good plane of nutrition. If the bird is on a seed based diet, a vitamin/mineral supplement is advised. Birds on pelleted diets may or may not require an additional source of calcium. Over supplementation can be dangerous, and we recommend that the diet of a hen who lays be discussed with your avian veterinarian.
Examine the egg. If the shell is thin, soft, excessively rough, dented or misshapen, the hen's nutrition may be inadequate and should be addressed immediately. These birds are at an increased risk for a difficult lay, egg binding and broken bones. Abnormal shells are also often the result of an infection somewhere in the reproductive tract. Seek veterinary advice as soon as possible.
What You Can Do
Consider the stimuli which encourage the bird to lay.
Disrupt the bird's routine by rearranging the cage or changing its location. Remove nests and nesting sites.
Do not physically stimulate the bird by stroking her back or tail head.
Remove objects, such as mirrors or toys to which the bird may have formed a sexual attachment.
Do not simply ignore the bird if she is bonded to you, but distract her and redirect her attention. In the case of larger parrots, maintain your place as head of the flock and reinforce this in your bird's mind with gentle, but firm enforcement of rules.
Although some hens will cease to lay if the eggs they are incubating are removed, most respond better to having the clutch number completed by the addition of scotch mints, white marbles or similar mock eggs. These can be left with the bird for the natural incubation period.
For the companion bird, breeding is not usually the best solution. If you do elect to place your hen with a male, research the possible outcomes carefully. Your relationship with your bird may alter drastically, the pairing may not be successful (birds have minds of their own) and the risk of disease transmission is real. Never pair your bird with one whose health status is unknown.
In cases where another bird (not always a male) is already present and laying is excessive, separation or other changes in the birds' routine and environment may be necessary.