I personally do not see a problem with using animals as food. If that's good enough for all the other omnivores and carnivores in the food chain, it's good enough for humans. There are certainly a lot of problems with the sustainability and humane-ness of our livestock farming, but I don't see "become vegetarian/vegan" as the only solution, or even necessarily a desirable one. But getting into a meat vs. no meat debate here isn't ever going to be productive, so that's all I'll say.
I had not known that male chicks are killed after birth in such numbers, and the practice does make me sad. But I also recognize that a lot of people just don't have any kind of emotional response to this sort of thing, and that's ok too. It's great that people are building new technologies to allow us to keep doing what we're doing, but with better treatment of the animals involved, and less waste.