My duck is 1yrs, she has been fine until two days ago she came out of the hut and cld not walk... she has not laid for 3 days now although there is an egg there, she loses her balance and is moving using her beak and the bend of her legs, she is still eating and drinking fine, we have given her yeast to her diet and she is fine in her self, so please help me, as she is so young and my daughters pet x