We have a group of ducking that hatched about a month ago. Since the weather is so warm down here, they have been outside since they were about two weeks old. Though they have plenty of shade and access to a tub of water, during the day most of the ducklings are panting with the heat. Lately, however, we have noticed our one male Welsh Harlequin panting even in the cool weather and at night. He is very weak on his legs, they shake if he stands for too long and he tends to lay around more than the others. Also, we noticed yesterday that what appears to be his 3rd eyelid is looking red. He is still eating and drinking and getting around for the most part. I should add that he and his two WH sisters are HUGE. They are about twice as big as the runner/buff crosses that were incubated and hatched at the same time. Any ideas what is going on with this poor little guy?