hi my pups are 4 weeks old they had been out in the garden from about 10 in the morning till about 9 at night they are in a big pen when would it be ok for them to stay out over night.

What sort of sleeping shelter will they have?  Do you mean they will then have no time in the house at all?  They will all still need to spend good amounts of time in the house during normal activities ie housework, comings and goings of visitors etc. even if you can't manage them all in at the same time.  They all need to spent a good bit of time with humans learning the word No (mine rapidly learnt not to have a chew at the one rug in my kitchen) even a move towards housetraining.

I would agree, even if it is easier with a sizeable litter for them to start sleeping in an outside kennel if space in the house is tight for a sizeable litter, or as in my case pups get very upset about not being able to get further from their beds to toilet, they should still be spending sizeable chunks of time indoors.

Mine get fed in the kitchen, and spend time therre playing when I am not busy in there using the kitchen for it's normal purpose (fortunately don't cook too much).

They should also come into other living areas of the house, preferably one at a time to get used to the TV, and the fact that this is how they would be in their new homes, way from the others in the human living areas.