Your efforts probably saved his life as the parents if they are chasing from the area, would try to kill him. Better to have him killed than go to a predator and the swans will protect their young in this way, especially if humans try to capture the young.

Please ensure that the pen is enclosed on the top and bottom so no predators such as fox, bobcat, coyote, etc, can dig under or climb into the pen to get to him. Finding him a good home will be the best. These must be wild swans since he is not pinioned, as most captive swans are required by many states to be pinioned and this should occur between 1-3 weeks of age. In any case, thank you for saving him. The Regal Swan