Feed sacks, the ever-useful piece of fabric. Not only can you make clothing, curtains and dish towels from them, you can make a shelter for your flock of chickens! Building a simple A-frame poultry shelter like this one requires 2x4 lumber and muslin chicken feed bags nailed over the frame. The bags are 100-pound bags of Gee Bee Egg Mash made by Grain Belt Mills, So. St. Joseph, Missouri. Chicken mash contains ground grains, proteins and legumes along with supplements like calcium and magnesium. Hens on mash will typically lay more eggs than hens not receiving mash. Laying hens need substantial amounts of calcium to produce strong eggshells.