I have a small flock of 4 chicken's 2 of which are white star's. 1 unknown. and 1 black Poland. my polish is a female and aprox 8-9 weeks old. she acts like a cat in the sense of she likes to be cuddled and lays up against me. sometimes while she's sat on my knee and i'm stroking her she makes this growl/purr noise. is it just the same reason that cat's purr or something.??