The Closed Gene Pool and Foreign Blood
A closed gene pool is more than just a gene pool which hasn't been outcrossed. It is a gene pool which has been maintained within itself for so long that any unconsidered outcross is more likely to create problems than enhance the gene pool. The genes in a closed gene pool are very stable and do not take kindly to being manipulated by anything but than an extensively researched and well educated insertion of foreign blood. This foreign blood should be from a related gene pool and no more than 25% of it should be unrelated to the closed gene pool. It should be added in thru the female side. Then the get from that breeding be bred back into the closed gene pool to re-stabilize the closed gene pool with the addition of whatever plusses were brought in from the foreign blood.
This is where many novices err. They believe they need to create "biodiversity" and found their flock by crossing strains. In closed gene pools and superior veteran line bred flocks ( both sometimes the same thing) this upsets the equilibrium of the gene pool and the novice spends years trying to re establish it or plain gives up. Research is your friend. The breeder of your birds and the history of the breed are also.
Best,
Karen
Interesting Karen as I brought in English bred Orps and used them on US Orps.That was a cross that had not been done in years.The MALE has been dominant in improving on the US birds, not the female.