Make sure that the donkey will be friendly with your birds before buying it. I had a donkey that was agressive to our dogs and cats but then also attacked my ducks and geese when they got into her pen. She stomped on one of my ducks and broke its wing, leg and back. My DH put her down for me. My chickens would go out there but the donkey would chase them so they wouldnt stay long. I was told that if the donkey wasnt raised with the type of animals that you are wanting it to protect that it really wont. Donkeys are great gaurd animals but more for larger animals. If you allow free range it is pretty hard to prevent loosing one here and there, if they go into a coop at night you could try getting a couple of geese to run with your flock, they will interact with the chickens without much problem and are usually able to run some of the smaller predators away. Good luck. Jenn