Yes, there are many predators that will eat the young. They could also be drowning or wandering off and not able to get back to the nest. If there is something physically wrong with the cygnets, the parents will abandon them. However, since this is an on-going issue, it seems to be that of predators. Coyotes, foxes, turtles, large mouth fish, raccoons, snakes, egrets, herons, owls, hawks, eagles and other predators will eat young birds.

You can house them indoors, but you will need to have a water feature so the parents and young birds can swim. The pond/pool must be flush with the ground so that no leg injuries ensue and the cygnets can easily access the water and get out once they are finished swimming. Otherwise, they can drown if left in the water for too long.

The birds will need to be protected in the barn by a metal fencing on the bottom of the pen and on top of the pen so that no predators can enter the barn and dig under the pen or over the pen. The ideal solution is to build a pen as described above 1/2 in the water of the pond and 1/2 out of the water so that ample room to dry and preen along the bank is provided. A feeder filled with a mixture of cracked corn and poultry layer pellets should be placed inside the pen so that the birds have access to the food. For the cygnets, you may need to have a small dish near the bank so that they can feed and you need to show them how to feed and make sure that they are eating. See previous posts on this website on how to construct such as pen as they are photos.

If you cannot build a pen in the water, then the stall idea is good, but again, you will need a flush water feature so that the birds can swim and you can raise the birds in the stall for about a month until they can fend for themselves. Good luck. The Regal Swan