Therefore, when purchasing initial breeding stock, the breeder seeks a group of birds that will most closely fit the purpose intended.
From the en.wikipedia.org
Whereas healthy stock from a reliable breeder will likely thrive, need little or no attention during their life, have been vacinnated and are known to be suitable to introduce into an existing flock.
From the guardian.co.uk
The Total Score Method is a method where the breeder evaluates and selects breeding stock based on a weighted table of characteristics.
From the en.wikipedia.org
For example, let's say that a breeder is pleased with the muzzle length, muzzle shape, and eye placement in her breeding stock, but wishes to improve the eye shape of progeny produced.