I've just learned of the event within the (UK) Labour Party known as the 'Chicken Coup' and it made me wonder: is it still a pun if it's a play on writing, and not the spoken word?
According to the Oxford Living Dictionaries, a pun is:
A joke exploiting the different possible meanings of a word or the fact that there are words which sound alike but have different meanings.
Neither of those criteria apply here, so the answer would seem to be 'No'.
My question is: if it's not a pun, what is it?