Orient your roost so the pvc feeder is a foot away from it otherwise it will be more than pine shavings that get into the feed. Also you'll want it a foot from wall so they have plenty space to roost. Many use 2X4 so feet are flat and warmed by feathers in winter. I did'nt use a poop board and have openings, to nest and doors, 4" up to provide 3 to 4" of pine shavings. Personally I just laquered the floor for seal when hosing out for spring cleaning.
As for air vents, no, that is not enough. There is a good equation for air venting if your roof is gabled. Sounds like your not going that route so keep in mind that do to chickens exhaling and general poop fumes each chicken requires minimum of 0.5 cubic ft per min of freash air. That's enough to circulate out fumes from poop and exhast the moisture to prevent frost inside your coop in winter. Believe it or not it's not the below 0 temps that damage birds in winter it's the moisture that frost bites their combs and feet at a mere 32 F if not vented out.
With a gable sloped from 4:12 to 6:12 pitch, physics dictates (tried and tested), that 2.5 SQ inches per bird per eave end and total in gables will provide 0.5 cubic ft per min air circulation. i.e, if you have 4 birds that would be 10 square inches vent along each eave and 5 square in each gable. To do that you can drill 6-3/4 inch hole per bird along eaves or just have continuous small gap along eaves. This is far more efficient than large vents at top and only works with proper slope so take this info with a grain of salt. Much more venting is needed if you go a different route. On my page you'll see I used far less than this by drilling holes and calculating in wind speed as I'm right on a river with constant wind...just to let you know I did'nt heat this winter and my coop never had frost inside.