Purslane! Spread around the seeds and it grows like a weed. Good fleshy plant for a salad, good companion crop, as it draws up nutrients for your other plants, Ms. Rabbit and my chickens love it too!
I only have a third of an acre, and limited gardening skills so growing grains is not in my near future, but unlike most suburban neighborhoods in my part of the world, I do not use chemicals on my lawn, mow as little as I can get away with and encourage dandelions, plantain, clover, and other...
Great thread discussion to help folks out of a jam! Foraging the flock as much as possible is good too! I'd be reluctant about soup unless it is homemade ... most canned soup is too salty. I keep low sodium canned vegetables around ... for us when we want, for chickens in a pinch, for...