Kittening and puppy pens can be very useful for keeping young kittens and puppies safe and secure allowing them to integrate within daily household living without the worry of getting into everyday household dangers. When old enough to climb the pens can have their door left open and still be used as a place of safty and comfort to return to or for when supervising of a litter of kittens or puppies is difficult or other animals need to be introduced gradually.