OK so it's not a coop . .... and they are made of plastic.....but a good idea! You can cap them off at night to keep out the critters.
Automatic chicken feeder/ could also work for a dog house dog feeder.
PVC Chicken Feeder http://theownerbuildernetwork.co/i2p7 Here's a chicken feeder that's easy to fill, hard to spill, safe from non-chicken life forms, weather resistant, easy to make, and inexpensive!
Easy DIY Projects
theartproject: PVC Pipe Chicken Feeder
DIY No Waste Feeder (might try this with 5-gallon buckets instead, since I have some of those.)
Home made chicken feeder
Great homemade PVC pipe feeder for the chicken coop! Food funnels in from both ends.
Chicken Coop Coop a Doop!
Chicken feeder...great idea, could use a small container, like a bucket from the hardware store
I like the bottom right one. How to Build A Cheap Chicken Feeder From PVC Pipes: http://www.mychickencoop.net/build-cheap-chicken-feeder-pvc-pipes/