Amount of a food item that contains RDA of calcium

The Recommended Daily Allowance (RDA) of calcium is approximately 500mg for fully grown rabbit that is not pregnant or lactating. The amount of some common food items that a rabbit would have to eat in one day to meet the RDA are illustrated below. The dish they are in is the same. It can be seen that it would be impossible for a rabbit to meet it's RDA by eating flaked maize. It might be difficult with spinach, broccoli and other 'high calcium' foods but it would be easy to exceed the the RDA by eating a lot of nuggets.

It can also bee seen that a very small amount of a mineral block would provide enough calcium and it would be easy to ingest excessive amounts if a rabbit decided to eat a lot of it.

2 Broccoli florets 2 Broccoli florets
15 Apples 15 Apples
63g Nuggets ( a handful) 63g Nuggets ( a handful)
Bananas (about 17) Bananas (about 17)
Carrots and carrot tops (1.5-2 bunches) Carrots and carrot tops (1.5-2 bunches)
Dandelions (178g) Dandelions (178g)
Grass (463g) Grass (463g)
Hay (113g) Hay (113g)
Kale (265g) Kale (265g)
Maize (10 cereal boxfuls) Maize (10 cereal boxfuls)
Mineral blocks ( 1/19) Mineral blocks ( 1/19)
Spinach 630g Spinach 630g
Spring cabbage (150g) Spring cabbage (150g)
Watercress (11 bags) Watercress (11 bags)