All of the young pups that I have had have behaved in a similar way and that is when they reach a certain age they work out that if they go in their kennel then they get stuck in there and a young pup would rather be out running around having fun.
So with each pup when they get to this stage a have to be careful on how I deal with this situation and be careful that I don’t initiate the game of the big fat man chasing the quick little dog. So each time that Gus doesn’t want to go in his kennel a call another dog to me which Gus can’t help himself but also want to play so I just pick him up and put him calmly into his kennel.
Next stage is the collar and rope.