It looks like curly dock to me after googling. Thank you so much we have two growing going to be removing themIt might be curly dock??? If so, don't feed. Take a REAL deep cut with a shovel and see if the root is a carrot-like tuber. If so, it's dock.
That's actually my tortoise lolThat is a tortoise sculpture - I wouldn't feed that to your tortoises or anything else.