I think this is way out of line. (I also keep chickens, though not with the tractor I'm about to list):
Here's a $300 chicken tractor, complete package: https://www.aosom.com/pawhut-96-wooden-backyard-hen-house-ch...
Depending on your situation, you might not need much of a coop. I would expect you could get away with $100 in supplies, in the US--not using scavenged wood--if you didn't need an enclosure etc, and just a small coop with nesting boxes.
Chicks are $2 and less, so it seems absurd to pay $20 for a laying hen. In my area I think hens are worth about $6-$8.
Your 12 eggs/week (for 5 hens) was a bit low, but of course that can vary greatly by variety. Many hens can lay for 4-5 years, though, and slow down as they go. I'd expect near the end you'd get 12/week. FWIW I had 9 chickens and was getting 3doz+/week. If it was winter, you might have needed a light in the coop to extend 'daylight' hours. They lay more slowly in the winter.
My feed runs about $12/month in the winter, $3/month right now. I seriously can't see how you could feed 5 chickens $20/month worth of feed. Around here 50lb bags of layer pellets go for $10-$12. Plus I throw them scraps from the table, which would be waste anyway. I bought one thing of straw that is going to last about 2 years for $12 at TSC. I don't count my time--and actually, these days my six year old does nearly all of the work to take care of the chickens (releasing, feeding, locking up at night). The straw need not be purchased, though--plenty of substitutes could be had for free or cheap. Shredded newspaper would probably work.
For your $500 + $20/month I think you should have been able to handle about 15-20 hens and therefore triple your production, or make your money back in about 30 weeks. Even at 100 weeks, it's not a bad investment, IMO, given that it just generates money forever after that.