hormones

As fucked as the poultry industry is, that's not really a thing for a couple reasons. First is the FDA banned that practice, so in the USA at least you're not going to find any poultry products where hormones or steroids are used -- "hormone/steroid free!" is marketing BS stating they're not doing something illegal.

Second: we've selectively bred chickens (broilers) that grow so freakishly fast and big you don't need to give them hormones or steroids -- their bodies naturally produce excessive amounts. These are chickens that need their food supply controlled because they will literally eat themselves to death if allowed to. They grow so large and quickly it's common they develop leg issues leaving them immobile, and most will "naturally" start to die of heart attacks if they aren't killed after 8 weeks.