How much yarrow can I give?

Bandit is 7 years old now, he’s had chalky wee/bladder sludge for the last couple of years. He’s had a few flushes but really struggled to come round after the last one a few weeks ago, I’m trying to avoid another one!
Someone has told me that yarrow is good for cleansing his bladder. He absolutely loves it, snatches it out of my hand..I’m wondering if this is a self medication thing or just that he likes it and he’s a bit of a piggie
My question is how much can I feed him? He’s just over 3 kilos and at the moment he’s having probably 7or 8 sprigs a day. No adverse effects at all, and I started him on one and worked up. All good.

Any info would be greatly received..thanks x

I feed a lot of forage to my rabbits and whilst I try to provide a selection, there are definitely certain times of the year when they will get a large amount of just one type. I've never found any problem with this and of course none of the plants are new to them and their tummies. It's difficult to compare how much I feed with what you have described, but they certainly have a good few handfuls at a time. I'm also not aware of any special problem with feeding Yarrow and it's something that my rabbits also have.