I was thinking it probably means "not fed other turkeys", along with "turkeys may be kept 14 to a shoebox".
That second link does say something about being fed goats, so maybe the idea is that turkeys, in their natural habitat, are predatory pack animals like wolves or lions?
@Dammit started
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I was thinking it probably means "not fed other turkeys", along with "turkeys may be kept 14 to a shoebox".