Every one of them as yet untamed, about a hundred feral animals (5,4)

I believe the answer is:

alley cats

'feral animals' is the definition.
(feral cats)

'every one of them as yet untamed about a hundred' is the wordplay.
'every one of them' becomes 'all' (all of them).
'untamed' indicates an anagram (letters go wild).
'about' is an insertion indicator.
'a hundred' becomes 'C' (Roman numerals).
'as'+'yet'='asyet'
'asyet' with letters rearranged gives 'eyats'.
'eyats' placed around 'c' is 'eycats'.
'all'+'eycats'='ALLEY CATS'

I've seen this clue in The Guardian.

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