It could mean a lot of things. Maybe they are cold?
There is an earthquake
Shaking.
Sniffing.
shaking my body
There could be various reasons why a chickens beak is black. It could be bruising from other chickens or an infection.
It means they start shaking and they cannot stop, or they shake and keep shaking repeatedly.
smh = "shaking my head"
shaking her butt ...
Shaking My Damned Head
Means someone is shaking and dancing
Tremulous-quivering or shaking slightly.
Not if you mean "man-eating chickens" Chickens, being omnivores, will kill and eat small rodents and other animals. So the answer is yes, chickens can and will kill for food.