
I was so lucky that my Jozi (10 CC's and mother of champions) was still entire when I got her back at 8 months of age as I had originally sold her trying to be sensible in having a bigger age gap before keeping a puppy from her Mum.
Someone else in my breed went to the trouble of taking their bitch abroad to be mated, but only got dog pups, and they had a male who was not easy with other males.
One of these came back for re-homing at about 9 months already castrated with that typical Eunuch look, such a shame as he could have been useful in a breeding program and could possibly have been homed with someone willing to let him be used as he looked very nice except for the retardation in head development.
From a breeders point of view if something happens to the dogs one is using to carry on their line, a bitch develops Pyometra, then the entire animals in Pet homes can sometimes be used to rescue ones lines, by either having a bitch back on loan, or having a dog used on a suitable bitch.