Command - Down!
Once your dog knows the command SIT you can progress to the command DOWN.
Teaching DOWN is much easier from the sit than from standing, though you will progress to that as well. DOWN is a control/dominant position for the trainer and is a submissive position for the dog. Dominant dogs will resist in giving up a position of dominance, standing or sitting.
Some dogs will do a down more readily than a sit by their body type. Rottweilers and Huskies, in some sense all large breeds, for instance will usually find a down position more comfortable than a sit position due to their genetic body type. Labradors and Standard Poodles will take a SIT more readily not just due to body type, but sitting is their aware position and the position they are traditionally worked from. Jack Russell Terriers would rather stand than sit or lay down, and that is in their genes and mentality. Take your dogs breed into consideration when training either command.
You can use a leash or not for initial DOWN! training. I like to do without the leash for training the down if at all possible.
To start, get your reward treats bag and have a treat in your hand. Sit the dog in front of you. Make the dog aware of the treat, if she isn't already, and when her eyes lock on the treat lean forward with the treat held just below your eye level so the dog is looking directly at your face. Let the gaze fix for a second on your face. The dog is paying attention to the treat but your face is in the way. Hold it just long enough to fix that attention.
Push the treat toward the dogs nose, and when about two inches, from the dogs nose, lower your hand down and in towards the dogs chest. The dog's head will drop to follow the treat. Lower your hand to just above the floor and slowly pull it forward towards you. The dog will lower to get the treat. As it goes down, give the command "Fido, Down!" As soon as the dog is on it's belly, IMMEDIATELY give the treat. Scratch the ears and say "Good DOWN." You want to condition the action with the word. At first all your dog is interested in is the treat but quickly will learn the association. Do NOT let your dog lunge to get the treat. Do NOT give the treat until the dog is down. Do NOT reward for improper action.
Re-sit your dog and repeat as often as you have treats. Five minutes at this is a good time limit. Six to twelve successful repetitions is great for a start. Always finish on a success even if it is just one.
What if the dog won't go DOWN? If your dog follows with the nose and breaks the sit and won't go down, don't let it stand up. The only direction you want the dog going is down. Avoid pulling the treat too far out front or the dog will creep forward. Make it so the dog has to go strainght down to get the treat not forward. As the dog goes down give the command "Fido, Down!" As soon as the dog is down IMMEDIATELY give the treat, scratch the ears and say "good DOWN" You want the dog to associate the word DOWN with the behaviour. The treat is just a reward.
Still won't go down? As you pull the treat down, place your hand at the base of the neck, forward of the shoulders, and lightly push down encouraging the downward motion. You don't want to push on the shoulders as this can cause the dog to stiffen the legs to resist. Applying downward pressure forward of the shoulders tends to tip the dog forward and down. As the dog starts downwards give the command "Fido, Down!" As soon as the dog touches the ground give the reward. Scratch the ears and say "good DOWN"
If the dog resists the pressure and stiffens the legs and totally refuses to go down for the treat. First try a different reward, something the dog LOVES. This may be a toy, a piece of cheese, a small ball of hamburger whatever you can find that will give you a down. What is usually needed is three or four "downs" and the dog gets the idea of what you want. The "down" may be reluctant but the dog will get the idea very quickly.
Still not going down? Attach a lead to the training collar. As you push the treat down, pull firmly down on the end of the lead with your control hand. Again as soon as the dog starts down give the command "Fido, Down!" As soon the dog touches the ground give the reward IMMEDIATELY. Scratch the ears and say "good DOWN. Keep the downward pressure on the lead until you let the dog up. Repeat until the dog is going down on it's own, just one down on it's own and quit.
If this doesn't work you will have to resort to more physical means. Place your hands behind the dogs front ankles and lift and pull, giving the command "Fido, Down!" as soon as the dog is down IMMEDIATELY give the reward/treat.
If this doesn't work, if the dog yanks it legs back or pulls away you may have to resort to physically putting your dog down. This is very rarely required. IF you must resort to physically hauling your dog down, you must not fail, if you do fail your dog learns that it can resist and win. Push, flip, or lay on your dog and hold it down until you decide to let it up. Hold it down for a second or two after after it quits struggling. It only gets up when it doesn't struggle. As soon as the struggling stops say "good DOWN" and then release the dog. The release becomes the reward.
As soon as your dog is going down for the treat consistently start eliminating them. Limit the reward to every second success. Then every third success. Then go random, treat several times then don't treat. Eliminate treat/rewards as soon as possible! You want the dog to WANT to obey the command of the boss. That's you. The desire to please the boss should become the over riding desire.
Treat/reward training has only one problem: "dogs aren't stupid!" The know when you have that goody. If you give the command down without the treat/reward your dog will look at you like "yeahhhhh right" They KNOW when you have the goodies. Discontinue food treats as soon as possible! When your dog KNOWS the command start eliminating them very quickly. Praise, pats, scratches, belly rubs and HAPPY are the best rewards you can give your dog. When you, the BOSS is happy, your dog is happy out of her furry little body.
Plus it's not fattening.