a playpen/pen whatever they call them... My boy is 10 weeks old and sleeps on and off through the day and when it's lights out at about 11 pm he sleeps through until I come down at 7 am. The den is large enough for his bed, potty pad and his food bowls... He knows when he wants to go toilet as he cries, I pick him up and pop him on the pad, he does a turn and hey presto!
I do believe its because he feels secure and safe... Somewhere that's just his. It even has a zippy net roof for my peace of mind when I go out as he's found he likes to put his teddy on his bed and then climbs the mountain and tries to peep over the edge of the pen! Ha! Very resourceful little chap he is!!
I bought the medium size as the large took up so much floor space that he didn't really need as he gets plenty of exercise running around the lounge and kitchen when he's awake.
Just a thought and its the feeling of security the little ones usually like.
