The key objective of the RBST Poultry Project is to achieve improved strains of stock and for this to be met, there must be a plan. The approach that has been agreed is based on a clan breeding system – something that may be new to many poultry breeders.

A diverse gene pool is critical for any population if it is to respond to challenges in its environment. For a poultry population, the greater the genetic diversity maintained in the flock, the greater the chance that targeted traits will develop in its offspring. These traits can include faster growth, greater disease resistance, better egg production in winter, broodiness, a more docile temperament – the list goes on.

The opposite of genetic diversity is inbreeding depression resulting from excess breeding of too closely-related individuals, which, generation on generation, can lead to an increase in deformities and a decline in health, vigour, productivity and reproductive success.

Line breeding – the practice of breeding father to daughter or mother to son - is currently the most common form of breeding programme used in the poultry world. This is generally regarded as a better practice than breeding siblings and as a good way to establish a breeding flock if you only have one unrelated pair to work with. Line breeding can be done for several years without the need to introduce new bloodlines. By keeping the same genetic pool, faults can be eliminated as they arise through selection and as the gene pool narrows, generating only the desired characteristics, similar birds will be produced.

There is one significant proviso: line breeding only really works when you can start with well-bred birds that meet breed standard. Line breeding related stock year after year does lead to inbreeding which can lead to undesirable traits being carried forward.

Maintaining closed flocks without inbreeding

The alternative approach being taken by the Poultry Project is clan breeding, which is a way of maintaining a closed flock for many years without the problems of inbreeding. Clan breeding is the very opposite of line breeding as father and daughter will never mate and neither should mother and son.

Clan breeding requires at least three breeding pens of the same breed and a clan is a flock of related females that always stay in the same pen for breeding. Male and female chicks take the clan of their mother, cockerels are used only once in each pen never to return and after year two they are culled or sold. A reserve cockerel can be chosen from each pen as and when needed, but will never mate with females of the clan into which it was born.

The starting point

Selection of initial stock is generally determined by the number of unrelated cockerels available; one cockerel relates to one clan, two unrelated cockerels to two clans, and so on. For the purpose of illustration, we can take six breeding birds, three hens and three cocks – although it is equally possible to start with three trios or three quads – which will constitute three separate clans.

In the first breeding season, the cock is bred to the hen (or hens) in the same clan. On hatching, all chicks must be wing tagged for identification, with all chicks, both cockerels and pullets, assigned to the clan of its mother. Coloured leg rings are also useful to denote each clan – in this way, all of the hens can run together outside of the breeding season and be easily identified when the time comes to divide them back into clans.

In the second breeding season, all cocks move to the next clan over and any chicks born continue to be assigned to the clan of their mother and remain in it for life.

In the third breeding season the cock is again bred to hens in the next clan over.

In each breeding year, any defective progeny (comb defect, wrong colour legs, late feathering, lack of vigour) should be culled early. The rest are then allowed to mature to six months when hard cull decisions need to be made to select one or possibly two males (to give a reserve) and as many good females as there are from each clan. Males retained as replacements must always retain their own clan identification.

Key rules

- If a cockerel from one clan needs replacing, it must be replaced by a reserve cockerel from the same clan.

- After year 1, cockerels only ever mate with hens in the next clan over and never go back into the clan in which they were born to prevent sibling mating.

- Cockerels are used for one year only within each clan to prevent father-daughter mating.

- Never mix the clans or be tempted to use a cockerel from the incorrect clan, even if he is better than the selection from the correct clan.

Not enough birds for multiple clans?

 A clan breeding project can start with just one mating pair of birds, starting in year one by mating them and then in year two mating the best (F1) cockerel back to his mother. In year three, the same F1 cockerel, which is now the father, is mated back to his best daughters

 (F2) of the year two mating. From the resulting progeny, the best three pairs can be picked to establish three new clans. The alternative to this approach would be to team up with one or more other breeders so that together three clans can be established.

Making a real difference

The clan method of breeding is one that has the potential to make a real difference to rare poultry conservation. It is believed to be the best way to improve vigour, health and vitality, enabling reasoned selection for the most desirable traits while ensuring the risk of inbreeding is minimised. It will also help to ensure that rare but important traits are not lost while breeding to standard in relation to type.