Please choose the correct ending to complete the given sentence: Pets and Animals: [header] How to introduce a dog to pet chickens [title] Give your dog plenty of exercise. [step] Prior to introducing your dog to the flock, you will want to tire them out. Make sure they get plenty of exercise beforehand so that they will not use the chickens for play or exercise.

Ending1: [substeps] Take your dog for a long walk. Run a couple of miles with your dog. Ending2: Your dog should be able to run, hop, and leap, as well as walk. If your dog doesn't fit here, you can give them water instead. Ending3: A 20 to 30 minute walk with your dog will work both libido and problem-solving skills. Begin with walking for five minutes each day for three days. Ending4: [substeps] Don't push them too far back when they come out of their coop. Using too much force can injure them.

Answer format: ending1/ending2/ending3/ending4