People and animals bond better if they have the chance to have siblings.
I know terribly lonely people who grew up, and live sibling-less.
I enjoy watching my cats. We have 2 that we got separately. They don’t have blood relatives. They are very quirky. We have 4 that we got: they were bonded siblings that couldn’t be separated. Those 4 groom each other. They play together. They give way to letting the others go first to the food bowls.