My kittens are about 5 weeks now and very much alert like their mama... but I have them in a really big box in one of the rooms in the house that my mama cat picked on her own, it's more like a room that I have things stored in there but she liked it because it's less noisier than the other rooms and its mostly dark.

So... their able to climb out of the box but won't go anywhere far from the box, when do I start feeding them cat food and what kind? Can I leave them out of their box instead of putting them back in every time they come out?

They should already be eating kitten food, it is putting too much stress on mom expecting her to keep up feeding and it is very draining for her.

I can't recommend certain brands but basically anything that says it is for kittens (not cats) you can go with either canned food or soaked dry food.. they won't be to handle hard foods just yet.

Start with just a very small amount otherwise they will end up with diarrhoea and just build up the amounts each day until they are eating just the kitten food and not drinking from mum