@Kamelpov
There's a variety of reasons why farming isn't as successful post-apocalypse as it is pro-apocalypse.
1) In most developed countries nowadays, there's an extremely small percent of the population that actually farms for a living.
1a) They're also usually highly dependant on machines, which need various things to run, and then when they've done all of the work they sell the processed grains (we'll go with grains as an example) to a company that does a lot of things with it after that. Meaning they very rarely actually use anything they grow on farm.
1b) Animal breeders usually ship off their animals to butcheries as well, so they might not have the necessary tools to fully utilize all parts of animals
1c) Fruits or vegetables could probably be directly processed on farm, but it varies
2) Most farms take weeks to months to grow crops.
2a) That's months where potentially anyone could come by looking for food, and assuming that farms would have it, raid them and then maybe kill or enslave them.
2b) They wouldn't necessarily have enough food to sustain themselves for long, so they might have to head somewhere else for food like others. They could be killed there as well.
2c) Post-apocalypse tends to have various climate changes, which probably would decrease food production yields even more
3) Assuming there's still people alive, with the seeds, the tools and the knowledge on how to farm manually post-apocalypse
3a) Food production would be way less than it currently is
3b) The infrastructure to transform 'food materials' (grains, whole animals etc.) to processed meat (wheat flour, steaks etc.) on a large scale wouldn't exist
3c) The seeds to grow new crops might not be easily available, and the breeder animals to get new animals might not be available either, so large decreases there as well.
Basically.
Expecting anywhere near the same food production post-apocalypse is being gullibly naive, unless the apocalypse is something like massive vegetation growth or something similar.