My three chickens seem to have developed a bad habit of eating their pine shavings and also dirt; I noticed today that they had kicked a bunch of straw and mulch aside and were digging with their beaks in the dirt). Also, I noticed that one of them seemed to have a more pronounced breast bone. So, I am concerned that they may not be filling up completely on actual food - the layer pellets and the snacks (sunflower seed and blueberries mostly) that my parents give them. I plan to get a baseline weight on all three of them and to set up a second feeding station (so that the feeder's not as crowded when they go to bed and when they wake up). Is this normal behavior for chickens, and is there anything else you would do if you were me (check for nutrient deficiencies)? I did think of trying to find a place for them where they can be on grass, and will do if that's necessary.