Kiln for treating oats? (4)
I believe the answer is:
oast
'kiln' is the definition.
(I know that oast is a type of kiln)
'treating oats?' is the wordplay.
'treating' indicates an anagram.
'oats' with letters rearranged gives 'OAST'.
'for' acts as a link.
(Other definitions for oast that I've seen before include "Drying house" , "Oven for hops" , "Kiln for drying hops or malt" , "Hop-drying kiln" , "Cooker" .)