a mischief of mice Subjectmouse (mice)CategoryAnimals → MammalsConfidencehighAttestationwiktionary-attested 2 sourcesWiktionary - mischiefWiktionary - Appendix:English collective nouns
a mischief of rats Subjectrat (rats)CategoryAnimals → MammalsConfidencehighAttestationwikipedia-cited, wiktionary-attested 4 sourcesWikipedia - List of animal namesen.wiktionary.org - mischief - WiktionaryABC - ABC Creature Features—RatsWiktionary - Appendix:English collective nouns