What is most like a chicken?

A tree and a horse are most like a chicken. This is a brain teaser; the original question is what plant and what animal together are most like a chicken. Because of the phrase digital camera, the answer is a tree and a horse.

Such brain teasers look simple, but if you do not think about them often they are hard to spot. So when facing strange, completely counter-common-sense questions, try dropping your usual way of thinking and approach them from another angle.