I am building my coop and have my girls in a box built of pallets I get free at work. They perch on the rails of the pallets and I want to build them a proper place to perch. Can anyone advise as to the proper size for a set of rails for them to sit on? Is wood best? Is plastic too slick? I am on a strict budget and am trying to use the pieces I already have to improve the "coop" so a general size & best material would be a great help! They are full sized reds and will need a box for laying soon. They seem to have really big feet! Thanks for the help.