I've always had a young horse or two in the field, I train a bit here and there when I have time because I enjoy it... after a year or two, I sell it and use the money to buy another colt... never like letting go, but you can't keep them all...
As I have begun to raise my own dogs, I am running into the same dilemma.... As new generations come along, I find myself more interested in the training aspect of things than just overall numbers of hogs caught... With this, my more mature dogs become more of a hinderance to me than a help...
... I cannot, as much as I'd like to, keep all the animals I train. Quite simply, I just don't have the time to hunt them all... as much as I wish I did.
While you didn't specify...it would seem that it is not the exact same dilemma. Are those colts that you are training and then moving along ones that you have produced?
Either way, you have to make the decision as to what is best for you. It may mean that you have to space your breedings a little further apart, or doing some serious screening when you decide to move a dog....