Asked in Apostrophes and Ellipses
What is the correct grammarical spelling for mice's house?
In an open context, "mice's house" would be the correct grammatical usage. "Mice" is the plural form of "mouse," and when "mice" takes the possessive form it becomes "mice's."
And despite what another person answered, a mouse can have a house, even if that house is indeed a nest. We are not limited to the literal in describing habitations.