Australian-grown chia seeds were found to contain 90 nanograms of b12 per 100g:
90 nanograms = 0.09mcg.
Vegans are thought to need 1mcg (1000ng) a day.
I think that all raw plant foods contain tiny amounts of b12 and overall if we ate a fully natural raw diet we would get everything we need.
Vitamin B12 In Foods
Micrograms per 100-gr edible Portion
Green Beans 0-0.2 Beets 0-0.1 Bread, Wholewheat 0.2-0.4 Carrots 0-0.1 Oats 0.3 Peas 0.0-1.0 Soybean Meal 0.2