Thanks everyone for your help! Lilly is perfectly fine now and our insurance paid for the damage. Our neighbors just got their new pool finished last week and it looks great! I don't like to make assumptions because I know I could be wrong, but I believe that the other neighbor's dog chased her in. She has been running and chasing the horses for a while now and I have seen her lounge at my donkey's neck once which scares me. Also, we have to pregnant mares in the pasture and the thought of the dog chasing them or the foals and tripping them up scares me too. My dad called and talked to the owner about it so hopefully they will try putting up an underground fence for the dog.
Hast thou given the horse strength? Hast thou clothed his neck with thunder? Job 39:19