Pressure treated wood is not a good idea for roosts -- there is absolutely no reason whatsoever to use it, and it is not so great for chickens to be standing barefoot on p/t stuff for half their lives.
Vinyl would be too slippery.
Paint would be ok but get scratched off fairly soon so really why bother. A well-sanded surface does not catch particularly intransigent poo IME. If you are really concerned, give it a coat of mineral oil or linseed oil or something like that, to seal the pores.
Yeah I would agree about the Pressure Treated... there are all sorts of horrible chemicals including a lot of arsenic used in the curing process of PT wood. I had actually considered using it on the inside of my coop as well before my husband reminded me about the chemicals.
I was unsure about whether or not I should paint my 2x4 pine roosts... this thread helped me decide, thanks.
I grabbed a 100 year old 4x4 from a barn that fell down near my hunting camp.
I am going to run a power plainer over it this weekend.
I always loved that barn, there wasn't one nut or bolt holding any of it together.
It was all hand cut with joints that have special names that I don't know.
they drilled holes and then banged in wooden dowels.
To bad it fell down, but now I feel like I have a piece of history in my coop.