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.
Once your dog can stay in a sit for several seconds, you can begin adding distance. Place him in a sit and say “stay,” take one step back, then step back to the pup, give a treat, and your release word. Continue building in steps, keeping it easy enough that your dog can stay successful. Practice both facing him and walking away with your back turned (which is more realistic).
When your puppy comes to you, don’t reach out and grab him. This can be confusing or frightening for some dogs. If your puppy is timid, kneel and face them sideways and offer him treats as you reach for the collar. Never call your dog to punish! This will only teach him that you are unpredictable, and it is a good idea to avoid you. Always reward your dog heavily for responding to his or her name, even if they have been up to mischief!
It typically takes 4-6 months for a puppy to be fully house trained, but some puppies may take up to a year. Size can be a predictor. For instance, smaller breeds have smaller bladders and higher metabolisms and require more frequent trips outside. Your puppy's previous living conditions are another predictor. You may find that you need to help your puppy break old habits in order to establish more desirable ones.