"Where are those crabs running?"
Translation:Hova futnak azok a rákok?
Those "rules" have been discussed and even fought over by grammarians for hundreds of years. There are newspapers from the 1700s with famous writers writing furious letters about how terrible it sounds to end a sentence with a preposition, and others saying that that is hogwash.
I think the version without "to" sounds better.
Similarly with "Where are you going?" rather than "Where are you going to?" (which sounds borderline wrong to me, in fact).
where're you going? - is more a movement without direction. where're you going to - seem to have a purpose, a goal.
I guess we'll have to agree to disagree.
For me, "Where?" in "Where are you going?" is hova and asks about the destination of the movement.
There have been grammatical rules/suggestions in English that don't allow sentences to end with prepositions. For instance, that's what would make "where are you at?" or "where are you going to?" wrong or wrongish.
These restrictions are being followed less and less, I believe. Avoiding prepositions at the ends of sentences can make English sound overly formal and stilted:
-"The taxi pulled up." vs. "Up pulled the taxi." -"Who did you give it to." vs. "To whom did you give it."
You could read articles for days about this conundrum. Enjoy!!