Just what DO hens get out of pasture?

Given that pasture plays such a major part in the free range industry its real benefits still remain hidden in the grass.

Just how much nutritional benefit do hens derive from ranging? What contribution does it make to their well being?

A new publication at last has something definite to say on the subject. ‘Managing Organic Laying Hens’ is written by respected poultry vet David Shingleton and the Soil Association’s former advisor Jake Hancock and amounts to one of the most sensible, practical and informative works on the subject yet to see the light of day.

But if it is a must-read for anyone contemplating organic egg production and an informative one for those already involved, its view of ranging and pasture will also interest a wider free range audience.

Historically, say the authors, pasture was considered to contribute between five and ten per cent of a hen’s annual feed intake even though some producers claim they have achieved much more.

“Organic pasture, being generally more diverse and high in legumes can be a good source of energy, protein and fibre that can augment compound rations,” they say. “Pasture may also balance protein and energy given fluctuating season requirements. But possibly more importantly it provides nutrients including carotenoids, Omega 3 oils, vitamins and minerals, some of which have anti-oxidant properties.”

The range may also contain herbs with other health-promoting properties. And the contribution made to the birds’ health and diet by invertebrates is “potentially easier to quantify”.

But there is a problem. The greenery birds eat out on range is poorly digested because of the high amounts of fibre in its structure. So to achieve any sort of nutritional benefit producers need to keep the plants as young and leafy as possible. This can be done by rotation, by topping or by following other species around the range area.

Fresh grass can have a “reasonable” lysine and a high carotenoid but it is difficult to calculate just how much is available to the hen. It is therefore equally difficult to put a value on pasture in economic terms.

Given the variability of management systems, soil types and seasons the authors recommend that producers should generally assume no input from pasture. But they add, “There is no doubt that a healthy, diverse pasture will provide a valuable contribution to poultry nutrition and health.

“While it is possible to manage and manipulate pasture to improve its potential contribution to the bird’s nutrition and health much more research is needed in this area.”

Managing Organic Laying Hens is published by the Soil Association and supported by Defra and Organic South West. It costs £5.