In Need Of Help With Mooington

I have no idea how to get into the area where Mooington is. Can anyone help explain. Thank you.

 

So on Skien's Island, there's a ravine with a jail at the bottom. Explore the jail and you will hopefully find a locked door that requires a hopper thrown into a key to enter. Explore the jail further to find a mob with the key, kill it and you can access the cow

 

i have dropped the key in the hopper around 20 times already and nothing has happened

 

Is the hopper surrounded by emerald blocks? Did the key drop from a larger than average monster who can charge?

If not I think this is bugged. Maybe try switching servers and see if that works.

 

it is the correct hopper and mob and i have switched servers and waited a full night