I can only speak to the USA, but in my area the number one crop in this area is dent corn and soya. Of the corn grown here 40% goes into ethanol production, and 36% is used for animal feed.

Commercial poultry production heavily relies on grain -- typically corn. It's the primary ingredient in the processed feed overwhelmingly used for commercial poultry, as seen in this typical mix.

We absolutely grow crops specifically to feed livestock. And this is ignoring the 52 million acres used for alfalfa and hay-grass.

[–] SupraMario@lemmy.world 2 points 7 months ago

https://www.sciencedirect.com/science/article/abs/pii/S2211912416300013

86% of the global livestock feed intake in dry matter consists of feed materials that are not currently edible for humans

But it also makes an important contribution to food security through the provision of high-quality protein and a variety of micronutrients – e.g. vitamin A, vitamin B-12, riboflavin, calcium, iron and zinc – that can be locally difficult to obtain in adequate quantities from plant-source foods alone

Just because they feed corn doesn't mean it's edible to humans, a lot of the corn grown is left to dry on the plant and then harvested. We do this so we don't end up with another famine. Not saying corn is what we should be growing for that, but it's a very easy and hardy plant.