I like all these ideas! Thanks for starting this thread.
@AltonaAcres, the feedstores might be closed for mandatory govt imposed reasons, or trucking companies might not be able to run, or it's the apocalypse and there's no more gas in your truck, etc.
We went through a lot of feed this winter, and I was wishing I had prepared ahead to limit that. So regardless of our current situation, learning ways to reduce the feedstore bill would be great!
Seasonally, spring and summer and into fall should supply many wild-harvested items. We should probably all learn what wild edibles are growing in the woods and ditches around us, for our own sake. Chickens will eat meat, so any little wild critters that you might not be willing to eat, your chickens might be happy to consume. In addition, any food that goes slightly off (like cheese), they'll happily take.
Winter will be your challenge, so collecting nuts, seeds, grains, etc. during the summer and fall will be essential. Maybe grow some root crops that will preserve well, or harvest and freeze greens if you have freezer space. Frozen lettuce and dandelions? Yum to them!