Was the cygnet and the baby chickens in an incubator? What happened to the parents? Usually, this young of a swan cannot make it without the parents because they teach it how to be a swan, feed, bathe, preen and the mother keeps it warm. The chickens may have pecked at it knowing that it was not the same species. Was there any sign of trauma? The only other issue may have been that the young bird had something wrong with it in the way of a disease, illness or other negative health condition. The Regal Swan