My mom (born in 1960) has long searched for this book she read in her childhood. She consulted with librarians and even wrote a letter to the Toronto Star, but none of the suggestions were it. She gave up in the '90s. It was a picture book (for children) about a teenage girl who finds a den of orphaned fox cubs and cares for them in the den, rather than taking them home. The illustrations were in pencil crayon or pastel style. She believes it wasn't an old book back then, so it was probably published in the late '50s or '60s.