Wattles: Why?
On the question of wattles:
[Carolynn] Smith created four animated roosters. The animated roosters (see second part of the video below) all acted the same, performing the tidbitting routine over and over, and they all looked the same, except for their wattles. One had a normal wattle, one was missing his, a third had a wattle that didn’t move, and the fourth had an extra floppy wattle.
A test chicken would be placed inside a test pen with two “audience hens,” a couple of buddies intended to make the test hen more comfortable in the less familiar surroundings (fowl are social creatures). One of the videos was then played for the test chicken and her response was recorded…
—So writes Sarah Sielinsky (in Surprising Science) about the study “On the function of an enigmatic ornament: wattles increase the conspicuousness of visual displays in male fowl“, which appears in the journal Animal Biology.