Minecraft Spawner help?

I got a Mushroomcow spawner at Rogue because I need them for something and they're hard to carry for over 4k blocks as me and @John_0696 have discovered.

But it isn't working, and I'm ripping my hair out trying to figure out why.

Here's the setup around the spawner:

and here's a hole I made to let the sun in because it's underground.

What exactly do I need to fix to get this thing to work?

 

Uncover the entire grass area to be revealed by sunlight, if not I don't know..

 

Okay star, I got some help and i have figured out the problem, You put the incorrect block down, it has to be mycelium instead of Grass. I changed the flooring for it and now the mooshrooms spawn normally.



Hope this helps! :)

 

I'm an idiot.