“Down” is a skill that can take some time to build. Like “sit,” it’s a good idea to teach the behavior with techniques called luring and shaping.
Grab a tasty treat and hold it up to your puppy’s nose. This time, slowly lower the treat and push it slightly in towards your puppy. It’s unlikely that your puppy will snap down on the first try. It may take a few training sessions! Instead, mark and reward any partial downward movement. As your puppy continues to progress by dipping lower and lower, heighten your rate of reinforcement. Once your puppy’s elbows hit the floor, throw a little party for your puppy! Tell them that they completed the behavior by providing treats in a rapid succession.
Once your puppy is regularly completing the “down,” add your verbal cue.