Not sure about the playhouse - a large box with either a heat lamp above it, or an electric hen inside it, will enable you to keep an eye on them much more easily than in a playhouse, unless I've got the wrong idea about what this looks like. They do need light, either natural or from a bulb, and if you use an electric hen this ahs the advantage of providing warmth as well as training them to 'day' and 'night' from the start.
I've got a Brinsea Ecoglow, which is nice and simple, though I've only used it for quail not chickens. With the tiny quail chicks I found it wasn't warm enough for the first 10-14 days until they had feathered up a bit, even on the lowest height setting, so I start them off under a ceramic heat lamp suspended above the box. With the Ecoglow, they seemed to spend all their time under it keeping warm, whereas with the lamp they were out and about feeding and drinking much more in the spread of warmth that it gave. But as I said, that was just quail, and it may be that someone who has used an electric hen from the start for chickens can better advise you on this. I put a max/min thermometer in the box under the lamp at first, as to start with they need the same temp. as in the incubator, which is quite high, and they start to huddle and not feed if it's not warm enough.