The_v, 1 year ago

Chickens do not receive any hormones. It’s been banned in poultry in the U.S. since the 1950’s when it was tested and shown to be ineffective. Beef commonly gets hormone implants in their ears. No hormones are approved or used in feed.

The rapid growth of the birds is mostly due to selective breeding and nutritional improvements. The growth rate and adult size in animals can be massively changed by breeders. Just look at the Great Dane and mini-yorky in dogs.

They also use antibiotics in the feed to reduce the bacteria load of the birds. This does increase the growth rate and reduces sick birds and deaths. It is not a good idea when it comes to antibiotic resistance buildup in bacteria however.