In a large pot, combine the chicken, onions, yam, fennel, dill, and wine, and season with salt and pepper. Add enough cold water to cover. Place over high heat and bring to a simmer, then reduce the heat to medium-low. Cover and cook until the vegetables break up easily with a fork, 1 1/2-2 hours.
Remove the chicken from the pot. When cool enough to handle, remove the meat from the bones, discarding the skin and bones, and cut the meat into bite-sized pieces. Return the meat to the pot. If you’d like the soup a little thicker, place the pot over high heat, bring to a simmer, and cook, uncovered, until thickened to your liking, 10-15 minutes. Taste and season as necessary.
To freeze the soup, divide into several small containers for smaller portions or transfer to 1 large container and freeze for up to 6 weeks. To serve, thaw in the fridge overnight, then transfer to a pot, place over medium heat, and heat until hot.