When I let my chickens out they have access to our compost pile and love digging through it for whatever they can find however I do make sure I either bury the egg shells really well or smash them into small enough pieces that the hens cant tell what they are. I wouldnt want them to start eating their own eggs in the coop. The pine shavings do take longer to decompose and they will leave the compost with a higher acid content. So thats all up to you and what you prefer. I use a mix on the floor of my coop of pine on the bottom and straw on top so i can just scoop out the straw and throw the poop/straw combo right onto the compost pile and hardly ever have to put down new pine shavings
