Hybrid Vigour works for both animal and plant species, this will rarely happen in nature without human intervention.
All pure breed poultry are known as Rare Breed. Hybrids are a crossing of two distinct pure breeds and a cross breed is anything there after.
Before you purchase hens you need to do a little homework and decide what you want, so here is a little information which may help.
Hybrids are bred for either egg or meat production and will always out perform the parent stock. The birds produced for egg production are self sexing (males and females are a different colour), so being worthless the males are destroyed immediately. The hens are egg laying machines and will produce an egg almost every day for a year and then become a spent force. After a years laying they are unable to process calcium fast enough often resulting in miss-shaped or soft shelled eggs, at this point they are almost worthless and need replacing.
Hybrids are produced in huge numbers by commercial hatcheries and different types are given numbers as they are not a specific breed, they are only given names to make them more saleable to the public. Breeding with hybrids will result in Crossbreeds with a huge variation in colour and performance and will rarely perform as well as the grandparents.
Rare Breeds (pure breeds) on the other hand can be both excellent layers and good meat producers (dual purpose). There are a huge variety of breeds and colours available. Some breeds such as the Maran and Leghorn will come close in egg numbers to the hybrid in the first year, and all breeds will continue to lay for up to five years. To give you and idea of numbers a hen will lay approximately 80% of the number of eggs she laid the previous year. For Example: - 1st year 250, 2nd year 200, 3rd 160 etc.
Unlike hybrids they will breed true to type with the offspring being similar to the parents in looks and performance. So a two year old Rare Breed is still a valuable commodity as eggs are still being produced in reasonable numbers, and are perfect for breeding as the eggs are a little larger than the previous year resulting in stronger chicks.
Fully GrownHybrids will cost between £7 and £15 each, Rare Breeds between £12 and £30 each with some newly developed colours costing £100 and upwards.
If you can collect birds rather than buy from a market then I would advise you to do so. This enables you to see the parent stock and the conditions in which they are being kept. Be aware of what you are buying as some unscrupulous sellers may try to pass a hybrid as a rare breed. The black rock for example resemble's a copper black maran, and the ponte sussex is similar to a light sussex so make sure you Get what you pay for.