Store or train bird (7)
I believe the answer is:
rooster
'bird' is the definition.
(I know that rooster is a poultry)
'store or train' is the wordplay.
'train' indicates an anagram (I've seen 'trained' mean this (to train can mean to grow something into a shape)).
'store'+'or'='storeor'
'storeor' anagrammed gives 'ROOSTER'.
(Other definitions for rooster that I've seen before include "Adult male domestic fowl" , "Male domestic fowl (US)" , "Morning caller" , "American cockerel" , "Male hen" .)