Chicken with Croutons, Leeks, and Lemons

sourdough bread, torn into bite-size pieces (8 cups)

medium leeks, halved lengthwise and cut into 2-inch lengths, white and light green parts only

lemons, quartered lengthwise

olive oil, plus more for drizzling

Kosher salt and black pepper

bone-in, skin-on chicken drumsticks and thighs