It's really amazing how fast they go from teenie tiny little fluff balls to making you consider space. This is why I just can't do a indoor brooder for more than the first few days to just make sure they're all thriving. When I saw this pic I thought it was my own brooder for a sec, mine looks very much the same right now with 3 week olds. So this weekend the weather is finally improving here and I'm moving them to the coop. That said, I have them sectioned off from the bigs in my coop and they still have the MHP or plate heat... It's a small room with a ladder going outside to a really small run with a roof. So my opinion is that you have plenty of space right now. But in 2 weeks you're really going to want to give them a way to run around more, build up muscle, not pick on each other, etc. Not sure what your coop setup is.