In general, one of each sex is best. Males tend to challenge each other all the time, trying to nudge the other one further down the pack ladder. This can lead to frequent bickering matches, or even a few no-holds-barred fights, which is the very last thing you want in your home. This is far less common with two females, but they can still struggle to settle the decision of who is the alpha female – something that takes up a lot of stress time in a dog.
A pair of Korthals Griffon hunting dogs
This doesn’t mean that a male and female won’t bicker – and you’ll have the mating season urges to deal with – but on the whole the one-of-each-sex combination tends to work best.
As for three dogs, or more, you’ll have all the wonderful complexities of a wolf pack hierarchy to sort out. The dogs will achieve this on their own, but in those situations you really do need to choose breeds or mixes carefully.