So thinking about Bob’s Niamh’s roosting I was reminded of the Roovolution podcast episode I just listened to. Have you heard these theories or research? I have heard only some.
What do you think of this information?
First claim, that one eye is nearsighted and the other farsighted. You will see a chicken consistently looking at the ground things with the nearsighted eye and further things, like the sky, with the farsighted eye. They can do both at once. Seems to me we would be seeing a consistent tilt of the head.
Second claim, that in roosting, because they can do this unispheric sleeping, sleeping with just one half of their brain, they keep one eye relatively active, which will be the outside eye, the one facing away from the main group roosting, to be able to see a predator as soon as possible.
Third claim, in order to give the other half of the brain a sleep time, they’ll turn around while on the roost so that the first eye is now facing in and the other out. (If this is true, maybe this accounts for falling off the roost?)
Third +1/2 claim, this is one reason there is competition for the inner roosting spots, the coveted safer places, because there’s less urgency to keep a lookout, and - I’m not sure I remember this right - I think they said that in the inner roosting spots they can then have periods where they let both sides of their brain sleep at the same time.