The explanation behind this is actually pretty disturbing. Due to selective breedingthe growth hormones we feed chickens in America, the chickens become fully grown much earlier than usual. It's like the equivalent of becoming a fully grown adult by the time you are the age of five, but you still have the mental and muscle capacity of a five year old.
Between 1957 and 2005, chickens raised for their meat quadrupled in size due to selective breeding. They grow to their slaughter weight in just 6 weeks, and their legs often struggle to support their own body weight.
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.
I've raised Cornish crosses and fed them normal, quality feed without any hormones: they ended up looking just like the chicken on the right at about 8 weeks old.
They've been selectively bred over the decades to grow as fast as possible, as big as possible, docile, and stupid.
Hormones in farm feed have been abolished back in the 80s. This is from breeding selective breeds . Stop watching shitty Facebook videos. Your brain has been rotted.
I literally corrected the sentence from "hormones" to "selective breeding" and it's still factual. Simple mistake. I don't watch shitty Facebook videos, and my brain isn't rotten... I just miss remembered what I assume was the scene from super size me 2 mentioned by another poster.
I also included a quote and a citation and my original post about how they grow so large so fast they often collapse under their own weight.
Truly the greatest of errors misremebering that was because of hormones 🙄
Mis remembering hormones? Come on. That is a distinction you don’t ‘mis remember’ seeing as that was the catch phrase of the 2012 sensationalist click bait of the millennium for the PETA. That single phrase laboured under staged farm videos was essentially what dropped their credibility to zero.
You don’t mis remember what reduced an entire movement to fraud.
If you watch Super Size Me 2, they go into a lot more detail on why the selective breeding is so disturbing.
Amoung other things, the birds are bred for meat muscle development, their cardiovascular systems have not been equally enhanced and as a result, chicken farmers know that the birds are big enough for slaughter because some of them will just start dropping dead of heart failure.
Piggybacking on this comment, but i never realized until I started keeping chickens that meat birds get so disproportionately huge that you can't allow them to roost / have to have a ramp out of their coop. If they jump, they'll blow out their legs when they land and just...die. They're literally bred to be incompatible with life, as no one really needs them to live long anyway.