I put one in early with chickens. I think it gave them something to walk on other than their feed container. They would stand on the feeder so much and poop in it so I give them a perch to have something else to stand on.
I use a 2x4 nailed onto railroad ties that are buried in the ground. Looks like an H with this - part at the very top.
While the chicks were still in their brooder we made portable roosts by cutting an 18" piece of PVC and attached Ls, then a 6 inch piece of PVC, then used Ts for the feet. Chicks seem to appreciate roosts from week one.
My husband made a little 2X4 perch for my chickies also. I've had it in there since day one. Now their flying up ontop of their nesting boxes to perch....I'd better get the bigger perches in their soon.
i don't think u should do it any younger then umm 5 weeks, whenever they start jumping around more so u know they will be able to hop onto it i didn't put one untill like 8-9 weeks...