You're grossly overestimating the time it takes to raise hens.

I also don't think anyone is doing it because they think they can compete on prices with an industrial farm that keeps all of the hens locked up in a 2x2 foot battery cage their entire lives.

My hens are happy, they forage for bugs all day long (creating those delicious, dark-yellow yolks high in omega-3s), and gladly consume all of my excess food waste which would otherwise go into a landfill.