We had chickens when I was a teen. They regularily hunted, killed and ate small rodents, lizards/snakes and sometimes even small birds like young sparrows whenever they could catch them - everything that fits into a chicken’s beak is fair game. And it wasn’t exactly a pretty sight. Imagine a single panicked field mouse being chased by sixteen feathered mini velociraptors, all trying to kill the mouse first, and then all fighting each other FOR the (hopefully) dead prey, as noone ever wanted to share their kill.
Funnily enough, the rooster was was a cuddly little idiot. (he got beaten up by the hens occasionally)
And just t add some proof for some of the points above, here’s a video of a single hen killing a hawk (warning, it is kinda graphic). They don’t even need great numbers to shred their wannabe predators - one really p*ssed off chicken and an opportunity to strike back, that’s all it takes.