How long can a new 8 week old puppy go at night in his crate?

Puppies can be in their crates all night. Just make sure you let them out to go to the bathroom right before you go to sleep and as soon as you wake up in the morning.

You should get a crate that is just large enough for the puppy. If you want to buy a large crate because your dog will get bigger, then stick a box or some kind of separator in the back of the crate to make it smaller. This makes it so that the dog will not want to go to the bathroom in its bed.