Parsley is a well-loved food: almost all rabbits I’ve met love it. In fact, they love it so much that it’s a good way to get them eating again if they have an upset stomach 🙂 There are some things to consider when feeding parsley though:

Parsley is a calcium-rich food which also contains oxalate. This can cause bladder sludge or kidney stones if used as an everyday food. Here’s a good list of daily or weekly foods: https://rabbit.org/suggested-vegetables-and-fruits-for-a-rabbit-diet/

Parsley can be a strong diuretic for some bunnies. I accidentally found that out when our previous bunny Breintje suddenly started to pee like a fire hose. He produced massive streams of pee: he’d sit in his box like a good boy, but the stream was so strong that he peed a whole body length behind him. We’d even been to the vet with him, but they couldn’t find a direct solution either, so we were told to watch what he eats and experiment. I was on the phone with my dad, in tears about Breintjes mystery problems, when I mentioned that he loves his herbs so much. My dad suddenly said: “Parsley is used in our local folk medicine, its dialect name is “Piskroed”!”. Yeah, the stuff is called “pissweed” in my dad’s native Limburgish dialect… 😳 Well, mystery solved! Breintje quickly improved when we restricted parsley to an occasional treat.

I’ve always done this.  But ideally you would rotate it with other greens from the Leafy Greens I list here: https://rabbit.org/suggested-vegetables-and-fruits-for-a-rabbit-diet/