1) Picking out from others 
In biology, culling is the process of segregating organisms from a group according to desired or undesired characteristics. In animal breeding, culling is the process of removing or segregating animals from a breeding stock based on specific criteria. This is done either to reinforce or exaggerate desirable characteristics, or to remove undesirabl...
process of removing undesirable animals from the flock.
• (n.) The act of one who culls. • (p. pr. & vb. n.) of Cull • (n.) Anything separated or selected from a mass.
A method of removing and releasing lighter-weight fish from a livewell so the heaviest or tournament limit is retained.
Rejection & or removal of inferior cats/kittens from a breeding programme. 
The process of eliminating less productive or less desirable individuals from a herd.
The process of eliminating less productive or less desirable cattle from a herd. 
Cull'ing noun 1. The act of one who culls. 2. plural Anything separated or selected from a mass. 
the process that determines which animals in a herd will not be bred.
Process of removing animals that are below average in production, unsound, or undesirable.
To select the least desirable rabbits, and remove them from the herd
Culling is not just the killing of rabbits, but with that being said you do not want to breed or sell to potential breeders, bad rabbits these are to sold as pets only. Save The Best Eat The Rest!
generally refers to the putting to sleep of puppies who may be malformed or unhealthy.
The process of removing an inferior sheep or goat from a flock/herd.