Grant, we have been planting young figs into the ground, off and on, for around 6 years. have never lost any, and we are in a zone 5.
We always apply mice poison and that has in the past been a good control. Though we have not uncovered any figs to inspect them this year.
Last fall we bent to the ground around dozen different figs. We then cover them with earth, then aluminum insulation, and finally leaves.
We will start attempting this year to over winter them by growing some horizontally next to our basement wall, and simply covering with leaves.
We have read in the past, of people being able to grow figs as far north as zone 4, by bending them to the ground and covering.
Where in zone 5 are you growing your figs?
Bob, zone 5 Connecticut