That's a good point. A bag of feed (40-50 lbs) costs about $17 and that lasts at least one month. I refill their water about once a week. It's never empty and the system holds about 6 gallons, so let's call it 16 gallons of water a month. I've been getting about 25 eggs a week, so we can call that 100 eggs a month. As the other hens start laying, my costs should not increase.

Running some rough numbers it looks like each dozen is costing me about $3.30. Once they are all laying, I'd expect that to go down to about $1.60 per.