Yes, the grey cygnets will begin to turn white once they reach the age of juvenile swans. The white cygnets are a color variation known as leucism. There is nothing wrong with the cygnets, they are just lighter in color.

Size is due to several issues:

1. The size of the parents and the offspring they produce.

2. The food resources on one side of the lake.

3. The age of the cygnets. If they are younger than the group on the other side of the lake, they will be smaller. Most likely, the west side swans were hatched out a few days, if not a few weeks from the smaller cygnets. The Regal Swan