I figured it needed its own thread.

From Wikipedia

Table 1. Nutrient comparison of 1 oz (28.35 g) of wheatgrass juice, broccoli and spinach.

Nutrient-------Wheatgrass Juice-Broccoli--------Spinach

Protein---------860 mg----------800 mg----------810 mg

Beta carotene---120 IU----------177 IU----------2658 IU

Vitamin E-------880 mcg---------220 mcg---------580 mcg

Vitamin C-------1 mg------------25.3 mg---------8 mg

Vitamin B12-----0.30 mcg--------0 mcg-----------0 mcg

Phosphorus------21 mg-----------19 mg-----------14 mg

Magnesium-------8 mg------------6 mg------------22 mg

Calcium---------7.2 mg----------13 mg-----------28 mg

Iron------------0.66 mg---------0.21 mg---------0.77 mg

Potassium-------42 mg-----------90 mg-----------158 mg

Data on broccoli and spinach from USDA database.[3] Data on Wheatgrass juice from indoor grown wheatgrass.[2]

It does have an edge of B12. since chickens eat lots of bugs and B12 is stored very well by animals and needed in very small doses. I don't think many birds run into B12 difficulties.