I own chickens and have had a bullying problem in the past. In the winter they have a lot less space and they get bored and stressed easily. The hen that took the "rooster"/protector role started pecking the smallest and sweetest chicken and drew blood. I had to keep the small chicken isolated from the flock for a few weeks while its wounds healed and put special goggles on the bully chicken for a month- they prevent it from seeing in front of itself so it forgets what's there after a few seconds. Yeah they can be vicious, but it's definitely preventable if they're raised right instead of at a factory farm.

Won't pigs gladly eat a whole person

Jesus

I once read about a turkey that had to be wraped in a tea towel to allow a wound to heal as the creature kept pecking at it and ripping out pieces of flesh that would glady eat.

That is pretty high on the extreme behavior list. And I think it was a pet turkey.

I didn't witness it but there are a few chicken farms around the area - the kind where chickens can freely roam around a huge shed - and I was told from an acquaintace that works at one they had been on the lookout for foxes, as they had already destroyed a few coops around the farm.

One morning they arrive at the barn to find a few dead chickens and two foxes partially skeletonized on the floor. It was a gruesome sight and the recording from the security cameras showed the foxes had been completely overrun by a mob of angry chickens that pecked, kicked and essentially killed by the thousand cuts method the poor wannabe predators.

The few chickens the foxes managed to kill were not enough to deter the mob but instead served to further spur it into a killer frenzy.

Because foxes are a protectes species, they had to call the authorities to give notice and have the cadavers picked up. Even the municipal vet was horrified at the state the chickens had left the foxes.

Here is an alternative Piped link(s):

here's a video of a single hen killing a hawk

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I could keep these little dinosaurs as pets, with no other objective or purpose besides admiring them because they are pretty to look at and that would not prevent any of the behaviors I listed.

What I'm about to say may evade you but cruelty is not an exclusive trait to human beings and chicken are a good example of it. They can be extremely cruel towards their own kind just for the sake of it. Not out of scarcity of food or living space. Just because they want to make another animal miserable.

Hate animal fights. The only animal fights I'll condone involve two homo sapiens trying to pour each others brains through their hear onto the ground, by means of punches and/or kicks to the head, at the sound of a bell.

I had about a dozen chickens in an outdoors coop, with plenty of space (about 32 cubic metres of tridimensional space) and often carried them around in a chicken tractor (birds of prey area where I live) for grazing and some individuals exihibited extreme behaviors.

Again, variations will occur from breed to breed and from individual to individual.

Some breeds are especially known for being tamer than others and more concerned with eggs and brood than others.

I'll partially agree on your statement that all roosters are assholes: we had one that enjoyed crowing when we were trying to talk anywhere in the bird's line of sight.