Good cross?

Buddy of mine owns world champion goose. Strictly a bay pen dog. He is now a 5X and will be trying for 6 starting in about a month. When he realized what he truly had he made the same cross again and again and again and again trying to get more. He’s produced some great dogs and I don’t know his percentages and what not but there’s still only 1 goose. I know when we had running hounds we liked to use uncles aunts and cousins to keep a line going. Tons of ways to go about it and the closer the cross is a good way to see the bad faults just as much as the good. Some lines can take an extreme amount of close breeding and some simply just can not. In game chickens it’s pretty common to breed an old cock to a young pullet or a young stag to an old hen. They seem to not produce as well the more they age and using something old with something young seems to help. Tons of different animals peds to study to see how the rest of the world tries to reproduce something .. hounds .. bird dogs .. game dogs .. race horses .. game chickens the one thing most all of them have in common is they are judged on performance and the ones that are more successful are completely performance based