What are the collective nouns (nouns of venery) for hedgehogs and foxes? Depending on the source you consult, for “foxes” you might find “earth,” “leash,” “skulk,” and “sounder.”  For “hedgehogs,” you could find “array” and “prickle.”

Mental Floss offers “array” here, along with more interesting facts about hedgehogs. agrees that groups of foxes are an “earth,” a “leash,” or a “skulk.”  

For more about collective nouns, see James Lipton, An Exaltation of Larks (4th ed., NY: Penguin Books, 1993).