Chicks and their new hen house thingy

[RAWR]

How old do chicks have to be before they're old enough to be moved out into a hen house? i have 5 four week old Rhode Island Reds (two hens and three roosters) and their starting to get way too big for the pen that we're keeping them in. And if they're old enough, how big does their hen house thing supost to be? Also, what kind of things do chickens like to climb on? (Im new to all this so ya know lol)
Thankiez a million :]

 

[crazyhen]

Move them now! I move mine out at 3 weeks into a secure coop. Reds esp can become aggressive toward each other if too crowded. I hang a light on one end so if they get cool they can get warm other than that no special treatment. Oh do not add to an established flock until they are about 17 weeks old and are about the size of the other hens. gloria jean

 

[RAWR]

ok :] thankiez