I have had a variety of small mammals go after my strawberries, ripe and unripe, before.
Thinking about hugels, do you notice any vole/mole/mouse pressure? In my experience, I have a very well fed chipmunk who I have a steady peace treaty with over the last couple years. I plant him his own strawberry plants and I have a more protected section for me. He has, in the past, hoarded the berries in one foul swoop so I'm leaning towards those pesky little critters.