My daughter's big white duck just died & we have no idea what might have happened. He was about 4-5 months old & was doing great. Big airy pen with a deck & swim area as well as a little house to go into. About a week ago I noticed he wasn't eating very much, but was still his energetic, squawking self. Last night he was sitting down instead of running up & down the fence line of his cage area but got up & started "talking" to us. When my daughter went out to feed him this morning he was laying on his side & was dead. We just started raising chickens a year ago & this was our first experience with a duck. Does anybody have any idea what might have caused this?