Life on crisps affected fertility (12)

I believe the answer is:

prolificness

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'fertility' is the definition.
Both the definition and answer are singular nouns.
Perhaps there's an association between them I don't understand?

'life on crisps affected' is the wordplay.
'affected' indicates an anagram.
'life'+'on'+'crisps'='lifeoncrisps'
'lifeoncrisps' with letters rearranged gives 'PROLIFICNESS'.

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I've seen this clue in The Times.

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