Backyard chickens provide so much for us and for the garden but don't forget their eggs.
When you boil eggs, don't toss the water. Save it and once it is cool, pour around your plants as a calcium boost for the garden.
And as for the shells, I always save mine. I have an old bowl I keep in the oven and I take all the eggs shells, give them a quick rinse and then toss them in the bowl in the oven. They get good and dried out and then I place them in my mini chopper and grind them up. You can sprinkle in the garden to add calcium but they are also good to put around the perimeter to keep snails and slugs at bay. The hard shells are not nice to their slimy bodies. You can also feed the ground up shells back to your chickens for added calcium to produce strong egg shells.