The down seems like such a simple behavior, but your dog's ability to be able to swiftly and smoothly down will save you points in the rally or obedience ring. You'll want to make sure your dog knows how to down from a sit and from a stand on a verbal cue only.
Laying down from a sit is a bit different than laying down from a stand. For the sit, the dog simply lays down. From a stand, the dog should go directly into the down without sitting first. In the following video, you'll see a down from a stand, followed by a down from a sit. Watch how Excel goes from a stand to a down without sitting in between.
Teaching the Down
I'm assuming most of you have a decent down behavior. It's fine if you still have to use your hand to guide the dog down, although I do recommend getting down on a verbal as it will make your life easier down the road. :-) When the dog is in front of you, say down, look at the ground, then follow with your hand and mark/reward when the dog's elbows hit the ground. I like to reward the down behavior on the ground with treats between the dog's paws. Pretty soon, your dog will start to drop his or her head when you say down in anticipation of your hand guiding him or her. Mark and reward that, even if the dog doesn't actually lay down! He or she is thinking, and that's a great thing! Before long, the dog will be laying down on the verbal only. Once you have it with the dog in front of you, work on it in heel position.
Here's a short video showing me using my hand to guide Excel into a down, which is completely okay in Rally! I also show him laying down in front of me.
Placement of Reward
Just like with the sit, placement of reward is so important to the dog's position. If you place the treats on the ground rather than in the dog's mouth, that will further reinforce the down position. I do occasionally reinforce the dog by feeding him or her directly, but I make sure the head is straight. If the treats come across your body, the dog will be more likely to down crooked. A crooked down is not the end of the world and would have to be pretty extreme (more than about 45 degrees) to lose points in rally, but it will be easier for the dog to begin heeling again if he's straight in a sphynx down, rather than a down on a hip. In obedience, straightness is more important.
You will see on this first video that when I cue Excel to down, he's a bit crooked. This would not at all be a problem in the rally ring, but if I reinforce him between his paws, or worse, between me and him, I risk making the position worse on the next repetition. So I choose to reward him on the other side of his front paws. As you can see, this completely corrected his next repetition, so instead of the behavior getting worse, it improved significantly with very little effort on my part - just good decision making!
Downs from a Stand
When dogs are taught to down from a sit, they may sit then down if they are cued while standing. Laying down from a stand uses completely different muscles and needs to be taught. I teach my dogs the same cue, down, for both. If I say down while the dog is standing, my criteria is that the dog lay down without sitting first. If I wanted my dog to sit first, I would say sit, then down. If the dog is standing when I say down, he or she should keep his topline level and lay down, not butt down first, followed by the front end. You can get as specific as you'd like with your criteria. In heel, I don't want my dogs to move forward, but just to drop where they are. If I am in front of them, I expect a fold back down. This is when the dog plants his front feet and bows back into the down. It's important that we teach the dog to go directly from a stand to a down. There are several ways to do this.
First, you can simply lure it. Take your treat and push it back towards your dog's chest. Most dogs will fold back with this motion. When the elbows hit the ground, mark and reward by putting the treats in between the front paws on the ground. The video below shows this.
Luring can work well if you get off the lure quickly. I prefer to use other ways to teach the down from stand. One way that I like to teach it is through a chin rest. If your dog has a chin rest skill, you can easily transfer this to a target, then put the target on the ground between the front legs. I've found this to be an easy and effective way to teach a down without a lure. Here is some video showing the steps. First I remind Excel about chin on a target. Then I work towards putting on the ground. For Excel I went through these steps pretty quickly, since he was familiar with this concept. If your dog is not, break it down further by doing lower chin rests and starting to mark and reward as the dog starts to lean down.
Once the dog is doing well, you can get clean training loops by rewarding your dog in a stand. Cue down, mark, and reward the dog high so he or she stands, then cue down again. This will create a nice clean loop that allows you to get in several repetitions.
Nitty Gritty Details
Some of you might want to be more particular on the mechanics of your dog's down. There are really three ways your dog can down. The first is a fold-back down. In this down, your dog's front feet stay stationary. From the stand, the dog simply folds back without moving his/her feet at all. From a sit, the dog must scoot his rear back in order to move into the down without the front feet coming forward.
Your dog can also drop directly into the down. In this case, the dog does have to move his/her front feet slightly forward but the dog's body and rear end stays stationary. Here's an example of that in heel position. You can see that Strive moves her front feet slightly forward, but does not move forward with her body.
Last, your dog can walk forward into a down. We don't want this one!
In this video, you will see what a dog needs to do with his body to go from a sit to a down while keeping his front feet in the same spot. Notice how the dog needs to scoot his butt back in order to keep his front feet in the same place.
In this second part of this video, we see the dog keep his body in the same place but lay down by bringing his front end forward.
Neither of these is wrong, it just changes how the exercise looks. It's good for us to realize that asking the dog to do a fold back down from a sit is a bit difficult for the dog, because the dog has to scoot back with his rear as he lays down.