The Duchess
Wise Old Thumper
I'm not 100% convinced the calcium in veg is worth worrying about over anything else. Take parsley - which is often quoted as a high calcium veg - even that only has 200mg per 100g. Which is only about half a rabbits daily calcium requirement and 100g of parsley is a lot! Yes, if you're feeding very large quantities daily of one of the handful of veg that are extremely high in calcium that could be an issue but I doubt very many owners do that. If you do, then just mixing up the variety more rather than worry about calcium is probably a simpler option.
I expect it is more likely a variety of factors, for example my local water has 125mg/l of calcium in the water. Drink 500ml and that's the same as a portion of broccoli. Reduce your veg and your bun will drink more water to compensate.
It sounds like your bun already has a very good diet, which also makes me think that some individual bunnies are more prone rather than diet being the only factor.
This is a very good point but I guess that just offering lower rated veg with a good water content could help compensate. I am now seriously considering bottled water for Tally to see if it helps her right now.