We have a 1 1/2 year old Call duck who is not acting like himself. He is still eating, but not as much. I even gave him some meal worms today and he left most of them in his bowl. That's not like him. When he poops, it is runny with no solids or color to it. He is sleeping alot more and is actually allowing me to pick him up and pet him. This is not normal for him. Can someone give me some insight? I am concerned about him. A fellow duck owner told me to add some raw apple cider vinegar to his water, which I did (Just a few drops) but he didn't seem to care for it all that much. Please help! Thank you!