Light For Eggs

ALAN HOLTHAM says laying hens can benefit from a low cost extension of daylight

- Alan Holtham

Light is a fascinating subject and one which has a far reaching influence in the natural world. Having been involved with light for much of my working life in the world of film and photography, I am well aware of many of its subtle properties such as intensity, colour temperature and wavelength, but I hadn’t really considered the effect that this could have on our humble chickens.

It is well known that chickens will lay fewer eggs in the winter months and that this is linked to day length rather than temperature. Under normal daylight conditions hens will lay most of their eggs during the spring and summer months, and then slow down or even stop completely during the winter. Pure breeds are more prone to a complete halt, whereas hybrids may keep going, albeit at a reduced rate.

The controlling factor for this is a small gland behind the eyes of the bird. This is the pituitary gland and is stimulated by daylight to produce a hormone that kick-starts the ovary into egg production. By adding artificial light you are effectively tricking the bird into an unnatural laying pattern.

This of course raises the ethical question about the long-term welfare of your birds and the effects of interfering with their natural rhythms. Commercially, laying hens are subjected to very scientifically calculated light regimes to keep them producing eggs virtually every day, but only for a period of about 18 months, after which they are effectively worn out and need to be replaced with younger birds. As a hen is born with a finite number of eggs already inside her, you are not gaining any more eggs by providing extra light, just controlling when they are laid. Once they are gone, they are gone, so if you are intending to keep your hens for their entire life, and are not particularly concerned with egg production, it is better to let them lay naturally over many years and just accept the fall off in the winter months.