Chickens Squishing Together in the Corner of the Pen

[Sinadrea]

About once a day my chickens will huddle or squish together as close as they can get in one corner of the pen. Some chickens appear to be on top of other chickens, but nobody seems to be upset, squawking, or even trying to wiggle free. They stand like that for several minutes, but move apart and will then usually do something like preen themselves. We even observed the one who is usually on the bottom climbing under the other chickens to get on the bottom. She was standing towards the back of the pack when we first spotted her.

It is the weirdest thing I've seen them do. I have no idea why they do this, but none of the hens or the one rooster appear distressed in any way with this.

Anyone else observe their with theirs chickens or have any idea why they do this??

Mine are 8 weeks old and they do this in the pen. I think it's to stay warm. They seem fine otherwise.