Depending upon where you are, different collective nouns have been used as a description for a group of hares.
You could use the following collective nouns as your answer.
A group of hares is called a …
Go ahead and try using it in a sentence. (1)
Lets see. What about, ‘a drove of hares just hopped past my home’. That would be quite a sight indeed.
We hope this has answered your question.