As a child, I remember my father using what was called Renardin. It was a liquid which smelled like a fox. You soaked string in the liquid (which was a orange/brown colour) tied it onto short sticks and enclosed your vegetables and other plants. This was before WWII and I have never come across it since. What it did was imprint in my memory the smell of fox so, even now, I am alerted to when there has been a fox about
This has not been very helpful because I don't think Renardin exists any more. Perhaps others might have a more practical suggestion. Our problem is muntjac deer which, in spite of stock fencing buried in the hedge, still manage to get in. They demolished our tulips this year and they love rose leaves.