I use two of these medium feeders for 16 (formerly 19) chickens (15 hens). We go through roughly 2-2.5 50 lb bags of commercial food a month. Very little spillage (my fault, not the chickens when I pour in the feed), and no one besides my chickens gets fed. Works great, just keep it covered and out of rain gusts so the feed will stay dry. I mount mine on pallets in the covered run. We feed a minimal amount of scratch grain and treats - when we go over a certain amount their eggs are smaller. My chickens do not free range due to predators.
http://ratproofchickenfeeder.com/
https://ratproofchickenfeeder.net/
Same guy sells through both sites, he also has an account on here, and a lot of folks on here have bought and reviewed his feeders.
I have 4 production red chickens (ISA Brown, golden comet), 1 buff orpington, 6 prairie bluebells, one olive egger and 3 starlight green eggers, all ~8-9 months old. The productions reds, BO, and SGE lay every day. The production red eggs are large to extra large, the SGE and BO lay medium to large. The PBB lay almost every day, and generally large eggs, but one consistently lays a medium egg, and they took a month or two longer to lay than the rest of my chickens. However, they have a high feed to egg conversion ratio, and lay almost every day, and the novelty factor of blue eggs makes them desirable here. Also the green eggs are a novelty and desirable here.
We get 12-14 eggs a day currently (one PBB is molting). We personally use 1-3 dozen eggs every 2 weeks or so, and sell 4-6 dozen a week for at least $4 a dozen. $64-72 egg income, $27.50/bag of food = my egg income pays for feeding my chickens, and my family's eggs are "free". Look at it this way, if you had a large breed dog, the cost of chicken feed is about the same cost you'd be paying for dog food every month. So the chickens are basically pets with breakfast benefits.
I think you need to reconsider your egg selling price and how you frame the cost of chicken food when discussing it with your husband. Also, if you can switch to production hens that lay extra large eggs every day, or at least a majority of your hens doing that, with some colored eggers for fun and customer appeal, that will increase your egg production while keeping your chicken feed cost the same, which lowers your feed to egg conversion ratio.
I get that you're trying to utilize the person food and garden scraps you have available to lower the chickens' feed cost, but if you feed production chickens more than 10% non-commercial ration, the egg size will decrease and your chickens may have nutritional deficiencies that show up long term and lead to lowered egg production and possibly decreased health. On the other hand, if you stick with heritage breeds, they can probably tolerate a person food and garden scrap diet slightly better, but because they too have been optimized to some extent for egg production and size (for dual-purpose birds), they will still need a significant amount of commercial feed to maintain optimal health, and then you are dealing with less egg production than for production breeds.
Good luck figuring it out!