Bird - Chronic Egg Laying

General information

Chronic egg laying occurs when a female bird lays more than the normal number of eggs or more commonly has repeated clutches of eggs, especially in the absence of a mate. While not usually harmful to the bird, chronic egg laying can be a drain on the bird's body and causes the owners quite a bit of concern.

Are certain birds prone to becoming chronic layers?

Cockatiels are most likely to become chronic egg laying birds; however, many species of bird can develop the problem. The reasons are not known precisely but this appears to be a species-related problem seen worldwide in pet birds.

What causes chronic egg laying?

We do not really know the answer to that. However, something stimulates these birds to lay more eggs than normal or more frequently than normal. A lack of hormonal balance that tells most birds to stop laying eggs obviously exists in chronic egg laying birds. Removing eggs that are already laid also seems to induce birds to lay even more eggs. Therefore they should be allowed to keep a clutch (there is a switch-off when full clutch size is reached) before removing eggs at the end of normal incubation period. Another theory is that many birds breed when they sense a nutritional 'flush'. High fat seed diets may do this and thus be the cause of problems. Similarly, presence of a nest box (budgies), mate calling (cockatiels) and abnormal light cycles may all act as triggers to lay.

Importantly, in hand-reared birds, the mate presence may be you! In these the need to pair bond is foccused on human rearers and over-bonding with an owner may precipitate over- laying.

Are there any health problems associated with chronic egg laying?

Since most of the birds with chronic egg laying are eating a poor diet consisting mainly of seeds, they are usually already malnourished. Egg laying deprives a bird of calcium. For normal birds this is not a problem as the body can compensate; however, for birds eating a calcium deficient diet (all seeds), hypocalcaemia may result. This can cause seizures, death or egg binding.

How is chronic egg laying treated?

First, make sure your bird is eating a proper diet so as not to become malnourished or to receive too many calories. A calcium supplement may be appropriate at these times. If you are removing eggs as they are laid, this practice should be stopped. The environment can be changed to try to reduce egg laying by decreasing the number of hours the bird is exposed to light and changing the location of the pet's cage. Owners may need to decrease the amount of time spent with the bird (and most importantly, re-establish a more platonic bond with the bird) until egg laying ceases or is reduced. If a male bird or nest box is present they should be removed.

Medical therapy may be needed. Hormone therapies (there are many regimes tried) can be of some use but will always need to be combined with environmental changes. In extreme cases, hysterectomy may be required to stop laying. However, this is a risky operation that will need to be undertaken only after full evaluation of the bird and then done by an experienced avian practitioner.

Above all, consult a veterinary surgeon for advice – the complications may be life-threatening and the multitudinous causes mean that a detailed investigation is essential.