This creature may be part hen
I believe the answer is:
panther
'this creature' is the definition.
(thesaurus)
'may be part hen' is the wordplay.
'may be' is an anagram indicator.
'part'+'hen'='parthen'
'parthen' anagrammed gives 'PANTHER'.
(Other definitions for panther that I've seen before include "Then rap the large black cat" , "Bagheera?" , "Black leopard" , "kind of feline" , "animal!" .)