Obviously corn is a suitable energy source for chickens, and like others have said it's probably more important what percentage of the feed is corn, than the fact that they are getting it at all. The commercial mixes are a good place to start, but clearly if they are adding vitamins and minerals, then the original mix is lacking. It seems hard to argue that there aren't healthier sources of energy, but we aren't just talking health here we're also talking costs. For me personally I'll take it, my pocket book forces me too, and I'm sure the chickens aren't too worried about it. Mine seem healthy enough providing me with a bounty of eggs and as far as I can tell they are pretty happy overall.
GMO crops, well that's a whole different topic. GMOs as far as I know are virtually indifferent nutritionally speaking (maybe someone has proof otherwise). However, it seems strange to me that a plant killer like roundup can be sprayed on a plant with no ill effect. I don't like the fact that Monsanto has a patent on a live creature, which is why I personally wouldn't plant GMO crops (contrary to what has been posted, most of what is available to the public is not GMO). I don't like the fact that these GMO plants can spread to other farms crossing with other cultivars, leaving those farmers on the hook (maybe this isn't true), which is definitely possible through plant reproduction. However, in a whole I don't see them as bad.
I used to be against pesticides, herbicides and fertilizers, until I took some horticulture classes and lost some of my own plants to pests. I can understand the need for these things, and the need for GMO crops.
What I do see as bad is the fact that we have 90% of our corn in one cultivar or a few very similar cultivars, which is controlled by Monsanto. The amount of seeds required to reseed each year may not be available from other sources, making Monsanto a monopoly in a sense. Yet this still isn't the largest problem.
The worst of all this is the fact that our way of life, low food costs and ample supply, is dependent on this current system. Disease, pest, & chemical resistance and control is of the utmost importance when we are monocropping thousands of acres. This is dangerous because we can lose a lot of food very easily. It's a problem because the land is over used, in most cases it absolutely requires fertilizers, pesticides and herbicides to be as productive as we need it to be. We need our to be this productive because we have become too familiar with low cost food, and we've let our farming community fall to the wayside leaving only about 2% to do the deed for our whole population. A small farmer cannot compete unless through a niche market, although this is slowly changing. Only large operations are efficient enough, and again, the larger and more centralized the operation, the more likely we can lose so much food it causes national & global problems.
People simply cannot stop eating, it's essential. If there is a shortage in food, even for a few weeks, there will be major problems.
Finally, back to the Ominivorous chicken, we can look no further than ourselves. I think of my lunch, a can of soda sweetened with corn syrup, some corn chips, and a lunchmeat sandwich(probably meat from corn fed animals), and I ask myself, how much corn is optimal for me and my chickens? My answer, probably less than we're getting now.
I don't know if the points I've added were already brought up, I didn't read every single post thoroughly, hopefully I didn't repeat much.
