My duckling has been sneezing lately. He has deep enough water to dunk its head. A few times I have noticed when it was clearing the nostrils that some stuff came out. It was close to the color of his food and it was kinda clumpy. I am putting vitamin/ electrolytes in water. Every once and awhile I'll notice he will open his mouth kinda like a yawn. Today I noticed a little bit of clear stuff in its mouth. He is acting normal and eating a lot. Should I be worried?