We did have 36 chickens until a gang of dogs helped themselves to 12 of them. Now we have 8 bantams 4 medium sized hens 4 dual purpose roosters and 6 heavy breed hens.
The bantams and the medium sized hens use very very little feed compared to the larger birds as others have said. The larger breeds seem to be constantly starving and will devour anything that even closely looks like food including my fingers. After these costs and pain are considered the bantams are a much easier breed to feed and ours are pretty productive layers as well. In the spring we plan to add more bantam hens plus try to hatch our own chicks from our BB Reds.
Currently we use Purina Layena and pay 12.50 per bag since the price was just lowered due to an influx of corn in the market. We go through about 2 bags of feed per month and we feed only layena, no scratch. We were previously letting everyone out to free range until they started going into the neighbors yars over two acres from there coop and our feed use was considerably less, however now they eat A LOT! We went from using 1 bag to 2. In the spring we will be purchasing Premier electric netting for the chickens so we hope to again have lower feed bill. We do also feed whatever scraps we have and for the past week I have been adding warm oatmeal to their daily feed. They still eat the same amount of feed but they need the protein.
As for pine shavings, I personally only use them in the winter, during the lawn mowing months I bag up dry glass clippings into empty feed bags and use that in our coops and nesting boxes. The chickens love this since there are seeds to scratch for, it also helps to keep the litter nice and loose making it a lot easier to clean out. Grass clippings are free as well so that makes them the best choice for us. You have to remember to only use dry clippings though so there is no chance of mold. We allow ours to dry in the summer for a few hours but in the spring and fall it can take a few days. If it rains on the grass we do not use it.
Good luck!
For a very nice coop delivered right to your door already set us and ready to use I can recommend horizon structures. They advertise in Backyard Poultry magazine.