A piece of wire in the fodder can be dangerous (5)
I believe the answer is:
hairy
'be dangerous' is the definition.
(I've seen this before)
'a piece of wire in the fodder' is the wordplay.
'a piece of wire' becomes 'ir' (I am not sure about this - if you are sure you should believe this answer much more).
'in the' is an insertion indicator.
'fodder' becomes 'hay' (hay is a kind of fodder).
'ir' inserted within 'hay' is 'HAIRY'.
'can' is the link.
Can you help me to learn more?
(Other definitions for hairy that I've seen before include "alarming" , "Scary" , "With locks" , "An ape may be" , "Having had a close shave? Not so" .)