I have one duck he used to gwt along great with our chickens. Lately he has been running toward them and pecking at there heads and chasing them into there house. Our duck normally sleeps with them every night. Tonight I was able to get him back to his own cage and to separate him from the rest of our 11 chickens. What should I do???? Keep him locked up ????? Please help me. I don't want to get rid of him.