Lemon Chicken and Rice With Kale

2 pounds chicken drumsticks
Kosher salt and freshly ground black pepper
2 tablespoons olive oil
2 large shallots, thinly sliced (about 1 cup)
1 teaspoon cumin
1 teaspoon saffron threads or turmeric
2 teaspoons zest and 1 tablespoon fresh juice from 1 lemon
1 bunch curly kale, leaves cut into 1-inch ribbons, thick stems removed (about 4 cups)
3 cups homemade or store-bought low sodium chicken stock
1 ½ cups basmati or long-grain white rice