Origins of Pooh, Owl, Roo, Kanga, Eeyore, Rabbit and Piglet (6)
I believe the answer is:
porker
'piglet' is the definition.
(thesaurus)
'origins of pooh owl roo kanga eeyore rabbit' is the wordplay.
'origins of' indicates taking the first letters.
The initial letters of 'pooh owl roo kanga eeyore rabbit' is 'PORKER'.
'and' acts as a link.
(Other definitions for porker that I've seen before include "A pig raised for food and named for its meat" , "Piglet," , "Little swine" , "Young fattened pig" , "Hog" .)