chicken ladder

crawling board

A plank with cleats spaced and secured at equal intervals, for use by a worker on roofs; not designed for transporting material.
References in periodicals archive ?
Slate and metal roofs are so slippery, I use what some roofers call a "chicken ladder"--two wooden ladders pinned together at their top narrow ends, and draped in an upside-down "V" over the roof peak so you can get up either side.