What is a good age to breed them?
OFA cant be done till 2 but a prelim can be done, and most other tests can be done at anytime.
I have bred a male at 1 and know many others who have too.

I say after two maybe three.
After all test and the dog needs titles at both ends first.

If it is my own male and I know he is going to finish that is different than breeding to an outside dog. Of course they would have to be titled.
But like with Jaz I was showing him and he did get his AKC champion and junior hunter title. We wanted to go to a higher hunting title but dont have the money to pay for training and do shows.