My 1 year old goose has started looking a little unkempt. Her feathers are not laying smoothly and I see her sitting on her belly while eating, as though she doesnt have the strength to stand. I put out layer pellets, hay, and vegetable scraps from the garden in the yard for all my animals. Can it be a lack of a certain vitamin or a sickness? I need some clues so I know where to start researching.