As far as I see it, there are two reasons to become a vegetarian: for health, and for ethics.
Reason number one is moot. The healthiest diet is one that has at least 3 servings of green stuff and 2 servings of colorful stuff per day, yes, but it is also one that includes animal fats and proteins. This can be achieved easily by lacto-ovo vegetarians, but the matter stands that cutting out meat for health purposes has no scientific finding.
Reason number two is what I find most fascinating. The goal is to reduce the suffering of others, and it is a very noble goal. To reduce suffering of animals, you must not increase demand for their deaths and mistreatment. A bird with ample food and space to roam seems happy to me, though others may define it differently, so I think organic, cage-free eggs should be a large part of anyone's diet - all the health, and none of the suffering. A justly run dairy farm gets excess milk from the cows - and does not remove the calf, so, again, much nutrition (for those who can digest it) for no suffering.
How else can you get increased nutriton for little suffering? How can you decrease demand while not causing your own suffering?
Enter, stage left: roadkill. This is an argument often brought up in debates. Why should the ethical vegetarian have anything against naturally-dead animals?
First, let me point out what would be wrong with this argument. First, it's not sustainable (or hygienic) to the whole population to wait until the animals die of natural causes to eat it. Second, it would increase demand indirectly because scavenger/hunter animals would have to hunt more.
However, in practice in our human culture, "roadkill" has some value. We try hard to get the message across that waste is worse than the killing - so why not reduce that waste? The scraps of meat on chicken bones that the more carnivorously minded would be dumped into the trash, which does no one any good. For a Vegetarian Who Picks at Bones, the leftover scraps provide nutrition without increasing demand. Further, taking those bones and making stock has an incredible amount of nutrition. Then the Picky Vegetarian can take the soaked bones, grind them up, and put them in raw dog food or use as fertilizer.
These are things society SHOULD do daily, naturally, as a part of course to reduce our impact on the creatures around us. Gathering up chicken bones may make you look a little crazy and desperate - but you are just making the most of your situation. How terrible it is to see those bones thrown away for naught! For the most devout ethical vegetarian, would it not be most ethical to take the bones and make stock, and provide the stock to the hungry? Or make soup for carnivorous friends in order to decrease their dependence upon factory produced meat based canned soups?
Maybe, eventually, you will find that there is no "roadkill" left, once you get non-ethical-vegetarians to adopt the practice of making stock, etc. At that point, that ideal point when society has found itself with an incredibly reduced amount of waste, I urge you to become strict vegetarian at your own discretion.
But, for now, what's stopping you from having making a little chicken soup from society's roadkill?