I started adding mulberry leaves free choice to Journey’s (18 months old) diet as soon as full size leaves became available this spring. Hay and fresh grass are also provided free choice. I would not make mulberry leaves the only free choice food. She is free range and lets me know when she is not happy with the available food. Weight management limits the amount of rabbit pellets I provide and the addition of mulberry has been helpful but is not a major part of the diet. The abstract below is helpful.
Nutritional quality of leaves of some genotypes of mulberry (Morus alba)
Int J Food Sci Nutr. Aug-Sep 2006;57(5-6):305-13. PMID: 17135021
This study was undertaken to determine the proximate composition, vitamins, minerals and the antinutritional factor tannic acid in leaves of six genotypes of mulberry. The results showed that in fresh mulberry leaves the proximate composition values ranged from 71.13 to 76.68% for moisture, from 4.72 to 9.96% for crude protein, from 4.26 to 5.32% for total ash, from 8.15 to 11.32% for Neutral Detergent Fiber (NDF), from 0.64 to 1.51% for crude fat, from 8.01 to 13.42% for carbohydrate and from 69 to 86 kcal/100 g for energy. In dried mulberry leaf powder, moisture ranged from 5.11 to 7.24%, crude protein from 15.31 to 30.91%, total ash from 14.59 to 17.24%, NDF from 27.60 to 36.66%, crude fat from 2.09 to 4.93%, carbohydrate from 9.70 to 29.64% and energy from 113 to 224 kcal/100 g. Among vitamins ascorbic acid and beta-carotene were found to range from 160 to 280 mg/100 g and from 10,000.00 to 14,688.00 microg/100 g, respectively, in fresh mulberry leaves and from 100 to 200 mg/100 g and from 8438.00 to 13,125.00 microg/100 g, respectively, in dried mulberry leaf powder. The minerals iron, zinc and calcium were observed in the ranges of 4.70-10.36 mg/100 g, 0.22-1.12 mg/100 g and 380-786 mg/100 g, respectively, for fresh mulberry leaves, and 19.00-35.72 mg/100 g, 0.72-3.65 mg/100 g and 786.66-2226.66 mg/100 g, respectively, for dried mulberry leaf powder. The tannic acid ranged from 0.04 to 0.08% in fresh leaves and from 0.13 to 0.36% in dried leaf powder.