Why and how do chickens purr?

[Chickens 103]

Well last time one of my condensed purred, she layed an egg on me...?

 

[Urchickchic]

It’s one of the best sounds in the world. My girls do it all the time when they dust bathe.

 

[TwoCrows]

I love when they purr! I love the sound, the way they glaze over, some like to be pet when purring. Fun chickens!