Quick Fern pruning question !

We have loads of self seeding [sporing @Selleri ! ] ferns around the garden, and everywhere around here, and I also used to grow the evergreen ones in previous gardens. I've never seen slugs or snails eating them either, and we have no shortage of those - eating everything they can.
Ferns never seem to get eaten, but maybe some more fussy ones are susceptible?
I agree that yours looks very similar to the ones we get all over the place @Millie16, so it's more likely that it's found it's way in there, and whatever was growing [deliberately] in the barrel has died. You can always stick some spring bulbs in soon if you want some colour in there before the fern reappears. Many won't mind sharing space with a fern, but the fern looks pretty big, so it depends how you feel about keeping that too.