This might not be the answer you expected, but I would highly recommend looking into the resources that The Church of Jesus Christ of Latter-day Saints has available in the Chicago area. The Mormons have locations known as Home Storage Centers[1] where members can buy non-perishable food items in large quantities at low prices so they and their families can be self-reliant. They are generally open to non-members using the facilities if they ask first, and for your cause I would be very surprised if they would not support you wholeheartedly. There is one less than an hour outside of Chicago[2].

If you need a member of the church or the bishopric (clergy) to vouch for you, please feel free to get in contact with me at sam (at) mangane.se.

Good luck!

[1] - https://providentliving.lds.org/self-reliance/home-storage-c...

[2] - https://providentliving.lds.org/self-reliance/food-storage/h... and search for Chicago to get "Naperville Illinois Welfare Home Storage Center"