Withdrawn advert affected market for cheaper poultry (4,4)

'cheaper poultry' is the definition.
The answer and definition can be both things that one consumes for nourishment as well as being singular nouns.
Maybe there's an association between them I don't understand?

'withdrawn advert affected market' is the wordplay.
'withdrawn' says the letters should be written backwards.
'advert' becomes 'ad' (synonyms).
'affected' is an anagram indicator.
'ad' written backwards gives 'da'.
'market' with letters rearranged gives 'rkmeat'.
'da'+'rkmeat'='DARK MEAT'

'for' acts as a link.

Can you help me to learn more?