Winston eats grass and also taught Ashii to get grass too

Down in Florida we don't have to worry about snow

but our grass doesn't grow that well in the winter.
As to greenies, JMHO but I wouldn't let him have them. I have heard some real horror stories about them getting stuck in their digestive track.....Maybe call and ask your Vet if the "kitty" grass is okay, just to be on the safe side. Or maybe one of the peeps here on the domain will know.
Luckily Winston and Ashi like the "beef sticks" but when they get smaller, I take them away. Winston doesn't swallow them, just chews the heck out of them.