Cat is part-hen, strangely (7)
I believe the answer is:
panther
'cat' is the definition.
(I know that Panther is a cat)
'part-hen strangely' is the wordplay.
'strangely' indicates anagramming the letters.
'part'+'hen'='parthen'
'parthen' anagrammed gives 'PANTHER'.
'is' is the link.
(Other definitions for panther that I've seen before include "Big cat" , "big pussycat" , "Black leopard" , "kind of feline" , "animal!" .)