It's not good for animals: for a start the meat industry is booming at the moment; secondly if enough people went veggie to actually affect the industry at all, and the demand for meat decreased, it would mean animals which were surplus to requirement. You're kidding yourself if you think that would mean they'd live happily ever after, as they couldn't be sold no one would want to keep them, and they'd still be slaughtered.
Think about it, the second farmers couldn't sell their livestock, the second they couldn't make a profit, they wouldn't keep them any more. Keeping animals isn't cheap, and to keep them, without profit, would be hugely expensive to any farmer. How many do you reckon would be prepared to make that kind of loss?
Now, what'd happen then? Maybe a few wild pigs or goats would stay alive, but for the most part it would be impossible to release them into the wild. The vast majority would have to be slaughtered.
I quote "If no one were allowed to farm animals, farms would grow crops instead. The first thing to go would be all the animals. Once the rural landscape were rid of cattle, sheep, and the like, fields would get larger, for the convenience of the combine harvesters, and hedgerows would go. Wild animals like rabbits would now be a more major pest. No farmer would want animals eating the plants, and so the war on such animals would intensify. Grown in the fields would be domesticate species of food crops, and so the number of plant species would decline."
Domestication is one of the best things that can happen to animals. If the golden eagle tasted any good you can bet your life it wouldn't be nearly extinct.
I quote "In the wild, a sheep would have to look for food, compete for it, jockey for position in the herd, look out for predators, guard its offspring, and it one day would die because of some accident, perhaps a fall, some nasty illness, or it would become weak and have its throat ripped out by the local predators. By striking contrast, the life of a farmed sheep is rather different. A farmed sheep has complete protection from predators; all the food of exactly its favourite kind at its feet all day every day, for which it does not have to compete; no competition for mates; no need to guard offspring; free health care; free haircuts; it is very unlikely to die in childbirth, and unlikely to die a nasty death. True, half a ewe’s offspring are taken away and killed. However, in the wild, a ewe would lose most of its offspring anyway, and in nastier circumstances. By the standards of the natural wild, a sheep’s life is about as cushy as a life could possibly be."
This is true, animals in the wild invariably die violent deaths. the closest an animal will get to dying of old age is being picked by a predator because it it old and therefore an easier to target. Farmed animals invariably lead happier, healthier, less stressful lives than those in the wild.
Vegetarianism doesn't save any animals, nor mean they get happier lives, nor does anything good for the animals at all. It just dissasociates people from meat, and means they can feel all smug inside that they are less cruel than those nasty meat eaters, and therefore better people. They're wrong.