Brooder box mirror fail

After placing a mirror in the brooder box in an attempt to help with their boredom.  I guess really they're probably NOT as bored as I think they are, but they seemed bored.  Fresh Eggs Daily or The Chicken Chick, I don't remember which, had written a post about boredom busters in the brooders, and so I thought I would give it a shot.  Overall though,  after having investigated the mirror, the chicks seem more scared of it now. 

Little Frog needs me & is signing at me asking to nurse, so I need to cut this short, but I'm thinking of using the old milk house as a larger brooder.  The walls are concrete, lack holes and other ways to allow drafts inside, the chicks would receive more "natural" light than they are now in the brooder box, I could use the old concrete milk tank to contain them, then when they start jumping out of the tank, I know it's probably time to start moving them into the normal chicken coop.  Actually in all reality, as awful as it may sound, the milk house would probably be significantly warmer than the normal chicken coop.  But... such is life.  I haven't even opened the door lately to know if it's even feasible to be used as such.  I know I would need to nail a piece of plywood over the doorway to the milking parlor, but other than that, I think it's fairly sound and "escape proof".