I have a young silkie, she's about 4 months now. She has started to do what I think is a cough but sounds more like a little hiccup. She does it periodically walking around. I have read about grape worm and she was shaking her head and opening her mouth but I only saw her do that for a few seconds yesterday she doesn't continually do it. She seems to be eating and drinking as usual and walking around fine. Any idea what this is/cause of it?