Can amaranth leaves (chaulai) also be sold as a crop along with grain?

Yes, amaranth has two uses. The leafy types, called chaulai, are grown as a quick leafy vegetable and sold fresh in the local mandi, giving fast cash from multiple cuttings, while grain types like rajgira are grown for seed. Usually you choose the purpose because the best leaf varieties and the best grain varieties are not the same, though some types are dual purpose. Leaf amaranth is a low cost, short duration vegetable with steady local demand and is easier to sell than niche grain, but the price is the normal leafy vegetable rate which moves with daily mandi supply. If your aim is grain for the fasting market, grow a grain variety. If you want quick local vegetable income, grow leaf types. Pick the variety to match the goal and confirm with your KVK.