Agriculture as it relates to growing vegetables and fruits is better for the environment and the overall health of humans on several fronts. First, there is no cruelty to animals from mass meat production. Mega farms commonly house chickens and pigs in large enclosed spaces rather than roaming free in a field. Eating vegetables and not meat reduces the carbon footprint on the planet--instead of feeding vegetables to animals, try eating the veggies first!
Unless meat is the only source of food for someone, animals should not be used for food as meat. In the case that meat is the only source, it is likely that they live in a hunter-gatherer society and keeping those animals in captivity is not likely. It is better to use animals for products like milk and cheese which are not violent methods.