Chicory is a woody, perennial herbaceous plant which has bright blue flowers. They are cultivated for their salad leaves, chicons or for their roots. The roots are baked, ground and used as a coffee substitute
The other name for chicory is curly endive, however they are two closely related species.
So can rabbits eat chicory at all?
Lets take a look at their nutritional data, in particular their calcium, sugar, phosphorus, fat, fibre, sodium and phosphorus content is of most interest as far as rabbits are concerned.
Nutritional value per 100 g (3.5 oz)
Energy 96 kJ (23 kcal)
Carbohydrates
4.7 g
Sugars 0.7 g
Dietary fiber 4 g
Fat 0.3 g
Protein1.7 g
Vitamins
Vitamin A equiv.
beta-carotene
lutein zeaxanthin
(36%)286 μg
(32%)3430 μg
10300 μg
Thiamine (B1) (5%)0.06 mg
Riboflavin (B2) (8%)0.1 mg
Niacin (B3) (3%)0.5 mg
Pantothenic acid (B5)
(23%)1.159 mg
Vitamin B6 (8%)0.105 mg
Folate (B9) (28%)110 μg
Vitamin C (29%)24 mg
Vitamin E (15%)2.26 mg
Vitamin K (283%)297.6 μg
Trace metals
Calcium (10%)100 mg
Iron (7%)0.9 mg
Magnesium (8%)30 mg
Manganese (20%)0.429 mg
Phosphorus (7%)47 mg
Potassium (9%)420 mg
Sodium (3%)45 mg
Zinc (4%)0.42 mg
Link to USDA Database entry
source wikipedia
As you can see chicory contains a hint of sodium, a lot of phosphorus and calcium, and is very acidic, plus has a hint of fat, fibre and sugar.
This means that rabbits can eat chicory but only in small amounts once a week at the most due to its calcium, phosphorus and acidic content. Nothing more that a few small segments will suffice.