I painted mine to make it brighter and primed the floor for the tile to stick better but as soon as it got cold out the tile came up one by one. Look into a glue/primer for stick on tiles (home depot) to save you money & work in the long run
I would paint it. My suggestion is get exterior paint, so you can get a toilet brush and a hose and clean it good every few months. Also, it helps see walls from the poop that always ends up EVERYWHERE. If you want to save money, go to a paint place and get mistinted paint. It's cheap and usually aren't THAT bad of colors. I am painting my coop when I get it done. I am going to select my color and have a whole chicky theme going on LOL.