Big Chicken and the Anthropocene.

Broiler chickens, in particular. The broiler chicken is the most popular breed of chicken produced by modern humans. If you go to a supermarket in any modern country, and see a chicken (dead, though living chickens are a thing too), it's probably broiler chicken.

Humans make lots of broiler chickens. 23 billion are alive at any instant, and each lives about 40 days (they grow extremely fast).

From ScienceDaily:

These chickens are an artificially evolved new 'morphospecies', the kind of thing palaeontologists recognise, that reflect a biosphere unrecognisable from its pre-human state and now dominated by human consumption and resource use.

"Since domestication there have been many strange and beautiful chicken breeds, but the broiler is perhaps the most extreme form of all. The body shape, bone chemistry and genetics of the modern meat chicken is unrecognisable from wild ancestors and anything we see in the archaeological record." 

It usually takes millions of years for evolution to occur, but here it has taken just decades to produce a new form of animal that has the potential to become a marker species of the Anthropocene -- and the enormous numbers of these chicken bones discarded worldwide means that we are producing a new kind of fossil for the future geological record.

Nothing is sacred and everything can be traded

I was at a vegan meeting and a speaker mentioned that changing to a pure vegetarian diet is a major decision in life, like changing a political party.

The aversion to new kinds of foods is unreasonable, and putting so much meaning to diet is too. I would eat meat and torture and kill whatever creature that I get the meat from if it would reduce $CO_2$ in the atmosphere by 1ppm. Meat is not sacred, nothing is. A creature killed accidentally is okay to eat, unless it would be better used not eaten.

For example, humans are not eaten since they are more valuable buried. Dead buried humans, covered in coffin planks, and decorated with protruding marble gravestones, engraved with magical incantations (epitaphs), are valuable magical artifices for keeping the human cultural system functioning.

3 great ways to humanely produce meat that probably won't sell well

Warning: this is like a Cracked.com list article, but try to take it more seriously.

1. Cancer lab meat. 

It might be a good idea to make lab meat out of cow cancer muscle cells.

Think about it, cancer cells are made to reproduce like crazy, so it might be a lot easier to make lab meat from cancer muscle cells, compared to using healthy muscle cells. And there has been precedence: the HeLa cells, famous for reproducing easily, are cancerous.

But when I searched, I cannot find any prior art on this. All that I could find were like "does steak cause cancer" and irrelevant.

Why it won't sell well: As rapid and cheap as cancer cell reproduction might be, it's almost certain that they won't make any structure. Tumors tend to be highly disorganized globs, completely different from healthy muscle tissue. As such, it would probably not taste like steaks. The only use would be for meat sludge, as used in meat nuggets, meatloafs, and meat stuffings.

Also, because of how consumers would be scared that eating cancer would give them cancer... even if they don't know that cancer isn't infectious, and they drink secretions from female cow's mammary glands without fearing of turning into calves themselves...