Thank you for your response to my question. The cygnet is approximately the same size as the rest of them. They are 10 weeks old (last week of April) so they do not fly yet, and are not pinioned. Today I built a pen for him on the pond and put him in it. The parents have been trying to get to him but I'm sure it is to do him harm, not protect him. They have been trying to kill him. I will watch him for the next few days and see hoe he does, if he is well I will try to find a home for him as I don't think he can go back on my pond. Thank you!