Goal:
Have puppy lie down on a low, stable platform with all four feet on the platform
What you need:
Non-slippery floor
One large, low, stable platform
Cookies
Your puppy
What to do:
Put a cookie on the floor or in a bowl, away from the platform for the puppy to eat
Lure puppy to stand with all four feet on the platform
Mark + treat
Lure puppy to follow the treat to lie down on the platform
Mark + treat
Throw reset cookie behind puppy
Repeat steps 2-6
Troubleshooting:
Some puppies may naturally follow the lure to lie down, whereas others may not
For some puppies, I may lure them into a sit, mark + treat the sit, then lure them to follow the treat into a down
At this stage, it does not matter how the puppy gets into a down position, my goal is to encourage them to lie down with all four feet on the platform
At this stage, I am also not worried about their down position yet. We will work on the proper position/posture after puppy can readily lie down on a platform
If puppy consistently falls off the platform, I would use a larger platform to help the puppy be successful
What the progression may look like:
Puppy sits on platform for 1 second
Puppy sits on platform then follows the lure and moves their front feet forward
Puppy sits on platform then follows the lure, moves their front feet forward but stands back up
Puppy sits on platform, follows the lure, moves their front feet forward and lies down with some feet off the platform
Puppy lies down with all four feet on the platform but is a bit crooked
How many reps? How often?
Learning phase: 3-5 reps/session, 2x/week
Maintenance phase: 3 reps/2 sets/session, 2x/week

