Another one that I've been watching recently is chicks knowing to take dust baths with zero interaction with adult chickens. One reason for this behavior is apparently pest control.
Same thing with cats liking scritches under their chin. They're not thinking "ah yes I am scent marking this human", scent glands are probably just itchy.
On the topic of chicks and dust baths, it's quite interesting because as soon as they encounter dirt for the first time they all do the same things. If you've never seen it I recommend looking for a video. But it seems like a weird behavior to have in every chick I've hatched. TBH, I love seeing weird inherent behaviors emerge like that.