Currently I have at least 4 ganders, 1 goose, and 1 that I'm unsure of, so I don't have the problem with deciding how many to have. However a friend of mine has a bonded pair of Pilgrim geese and 2 of their daughters hatched last year. All 3 geese are laying and only 1 goose's eggs are fertile. So I think it's more of a preference...personally, I'll always have at least 1 gander per goose.