Yes, this is normal behavior as the parents chase the juvenile swans prior to the new nesting season. You need to find the young swan a separate area on the pond so this chasing stops. Otherwise, stress can cause injury, dehydration, starvation, and illness possibly leading to eventual death. Should the juvenile leave the safety of the pond by walking into unsafe areas with traffic, domestic dogs or wild predators, it may get killed. If you cannot safely and adequately separate the juvenile from the parents, you may need to find her a safe home. If you cannot find anyone, please contact Bob Knox at Knox Swans and Dogs.

Unfortunately, this is going to be an ongoing issue each year for all the new juveniles that your adult swans produce throughout their breeding lifetime. The Regal Swan