Born after an average of 63 days of gestation, puppies emerge in an amnion that is bitten off and eaten by the mother dog. Puppies begin to nurse almost immediately. If the litter exceeds six puppies, particularly if one or more are obvious runts, human intervention in hand-feeding the stronger puppies is necessary to ensure that the runts get proper nourishment and attention from the mother. As they reach one month of age, puppies are gradually weaned and begin to eat solid food. The mother may regurgitate partially digested food for the puppies or might let them eat some of her solid food. The mother usually refuses to nurse at this stage, though she might let them occasionally nurse for comfort.
“Down” can be taught very similarly to “sit.” You can wait for your dog to lie down (beginning in a boring, small room such as a bathroom can help) and capture the behavior by reinforcing your dog with a treat when he lies down, giving him his release cue to stand back up (and encouragement with a lure if needed) and then waiting for him to lie down again. When he is quickly lying down after standing up, you can begin saying “down” right before he does so.
First, make sure your puppy is comfortable wearing a leash. This can feel strange at first, and some puppies may bite the leash. Give your puppy treats as you put the leash on each time. Then, stand next to your puppy with the leash in a loose loop and give him several treats in a row for standing or sitting next to your leg. Take one step forward and encourage him to follow by giving another treat as he catches up.
When your dog knows the release cue and how to sit on cue, put him in a sit, turn and face him, and give him a treat. Pause, and give him another treat for staying in a sit, then release him. Gradually increase the time you wait between treats (it can help to sing the ABC’s in your head and work your way up the alphabet). If your dog gets up before the release cue, that’s ok! It just means he isn’t ready to sit for that long so you can make it easier by going back to a shorter time.