Research suggests that dogs are able to recognize their siblings and their parents later in life as long as they spent the first 16 weeks together. Intuitively, the less time dogs spend with their families as puppies, the less likely it is they'll be able to recognize a family member later on.

Do dogs miss their siblings?

Dogs may remember their siblings (or rather their smell), but it's not that different from how they would remember any other animal (or person) from their past. If they associate them with safety and comfort they'll be happy to see them. But if they associate them with stress or fear they'd rather stay away.

Are dogs attracted to their siblings?

When boy dogs reach sexual maturity, they frequently mate with their siblings. They also may do the same with their mothers.