Looks like 1 week is not too early. We took a small box about 4 cubic inches....separated the top and bottom half to make our "end supports". Then took one of those wide sticks they give you at the box stores to stir paint with and poked each end into one of the boxes. Our chicks are a week old today, and the Barred Rock is already hanging out there regularly. She slept on it for a while yesterday with her poor little head hanging all the way down!
I've seen people make little T-squares out of scrap wood and put a dowel across...really anything wide enough for them to balance on without too much trouble, set not too high for them to hop up, should work. It only took them half a day or so to get used to it. It's very cute. Why not try it and see if they like it?
It DID unfortunately allow the Rock to poop nearly on the head of one of the Silkies. Just grazed her and came to rest against her cheek as she was sleeping. I felt a little bad. She kept on sleeping, however.