Yes, bobcats kill and eat chickens.
Deer
You can't. That is impossible. The only way to get feathers on Minecraft is from chickens.
2207 chickens
yes a hit to the skull can kill a deer
No. Lions kill deer, not the other way around.
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.
it can transfer diseases to human like bird flue ... !
people
you shouldn't be trying to kill a deer!
No not at all, in fact free range chickens will wipe out your garden faster than the occasional grazing deer. Deer are pretty selective in a garden and not at all nervous around chickens but a chicken flock will scratch and hunt everything green then root around in the destruction for bugs.
None. Lions don't eat deer, though they are more than capable of killing them, and deer don't kill lions. Deer choose to run or get the heck out of there over killing a lion, no matter how large the herd of deer is!!