And yet, they are not machines; they still feel pain, suffer, and wish to continue to live, and cannot consent to being used merely as food for humans. There can be no peaceful coexistence of humans and animals as long as the latter are considered property. The interests of the human will always win.
Those who work at the Peaceful Prairie animal sanctuary have seen first-hand the condition of animals raised in so-called humane environments. They take in rescued animals and treat them with the care and dignity that they deserve. They do not take or sell the eggs of the chickens and other birds, but give them back to their rightful owners, as their damaged bodies, engineered to lay far more frequently than they would in the wild, crave the calcium and other nutrients.
There is nothing natural, necessary, or humane about animal farming, whether for dairy, eggs, or flesh. Why try to justify it, when we can feed Earth's 7+ billion people with plants. Even someone with absolutely no ethical concern for animals whatsoever ought to have some concern for the future generations of humans, many of whom might be without food entirely if we continue the path we're going on now, cutting down rain forests to provide grazing land and crops to fatten cattle. It's simply unsustainable.