I was wondering what kind of corn you had that grew that many ears per plant...I've never had more than 2 or occasionally 3 ears on a corn plant.
To the original poster, if you have the means to grow some alfalfa or a small area of some sort of grain crop, by all means go for it. It will be a good supplement for them. I can't even grow grass where I live (northwest Arizona). Between the heat, lack of water (almost no rain, and our neighborhood's water system is terrible and sometimes we lose water to our house/property for a week at a time!), and all the wildlife, anything but cactus dies very quickly. We have a garden, and this last season we barely got any produce at all between the rabbits digging under our fence (It's buried over a foot down, in a trench filled with rocks and concrete, and they STILL dig through! Grr!) and the squirrels climbing through/over it. They would take a bite or two out of every vegetable, pull it off the vine, and then ruin it. And then dig up the plant too! We tried to grow a lawn, and the rabbits and quail ate up all the grass. Farming is hard in the desert.
As for cost efficiency, growing crops vs. buying commercial feed...I'm sure the commercial feed is cheaper if you add up the costs of water, labor, equipment, fertilizer....realistically you can't even make your own eggs/chicken meat in your backyard cheaper than what you get at the store. It's not a matter of being able to do it cheaper, but being able to make a better/healthier product, at least in my mind.
To the original poster, if you have the means to grow some alfalfa or a small area of some sort of grain crop, by all means go for it. It will be a good supplement for them. I can't even grow grass where I live (northwest Arizona). Between the heat, lack of water (almost no rain, and our neighborhood's water system is terrible and sometimes we lose water to our house/property for a week at a time!), and all the wildlife, anything but cactus dies very quickly. We have a garden, and this last season we barely got any produce at all between the rabbits digging under our fence (It's buried over a foot down, in a trench filled with rocks and concrete, and they STILL dig through! Grr!) and the squirrels climbing through/over it. They would take a bite or two out of every vegetable, pull it off the vine, and then ruin it. And then dig up the plant too! We tried to grow a lawn, and the rabbits and quail ate up all the grass. Farming is hard in the desert.

As for cost efficiency, growing crops vs. buying commercial feed...I'm sure the commercial feed is cheaper if you add up the costs of water, labor, equipment, fertilizer....realistically you can't even make your own eggs/chicken meat in your backyard cheaper than what you get at the store. It's not a matter of being able to do it cheaper, but being able to make a better/healthier product, at least in my mind.