That was a hint on the cause - why this evolutionary adaptation would emerge in the first place. For everything else - think what would happen in any urban are

That was a hint on the cause - why this evolutionary adaptation would emerge in the first place. For everything else - think what would happen in any urban area if a few poultry farms would close for a month. India is one single example of mostly vegetarian traditionalist population, but even in India in the tribes populated north and north-west regions vegetarian diet cannot sustain a population. Bonus question: how do you imagine a vegetarian Pakistan or any other middle east country? Do not bother to answer here.