I have about 20 chickens in my front yard. I have a chicken stick, set to very tight pattern. For the last couple of days, i have noticed that sometimes I have one or two chickens wandering in areas of the yard away from the stick. Why is that?
It's a bug. They were flying through the floor when I had them sticked in my house, and they'd wind up stuck on the floor below. In general, they tend to fly into the ground where they shouldn't be able to go and when they come out of it, sometimes they stop being tied to the stick.
Something in the code that has them desperately trying to fly away from you when squeezing them bugs out and ignores the ground collision in some moments. I even noticed this happening in Ur sometimes, without a stick to constrain them. I've seen chickens fly down into the soil and get stuck down there until someone shouts KFC near em to make them fly up.
Pigs and Chickens do not respect sticks if they aren't on the same level as the stick to start with (Pigs up on cliffs or furniture will ignore a stick on the ground, for instance). When a chicken dives into the ground, it might stop considering itself on the same level, and even tho it returns to the same level as the stick, there's no code telling it to check for the stick again. This is my theory.