Heat the chicken fat over medium heat in a small pan. Add the chives and cook for 30 seconds. Set aside to cool slightly.
In a large bowl, add the eggs, dill, seltzer, sugar, and salt and pepper and whisk until combined. Add the matzo meal and the chicken fat/chive mixture and stir to combine. Cover well and refrigerate for at least 8 hours and up to 24 hours.
Bring a large pot of salted water to a boil over medium heat. Form the matzo mixture into 8 equal size balls, about 1 3/4 ounces each, add to the water, reduce the heat to simmer, cover and cook until very tender, about 1 hour and 20 minutes. Remove with a slotted spoon to the pot with the chicken stock and cook for 5 minutes before serving. Ladle the soup into individual bowls and serve.
For the chicken stock:
Combine all ingredients in a large stockpot and add enough cold water to cover by 2-inches. Bring to a boil, over medium heat, then reduce the heat to low and simmer, skimming the scum from the stock with a ladle, every 15 minutes, for 3 hours. Strain into a large bowl and discard the solids.
Transfer to a large saucepan and cook until reduced by half. Add the roasted jalapenos for the last 10 minutes or of simmering, then remove. Season with salt, pepper and freshly chopped dill.
If you are concerned if the oils or other ingredients in these recipes are suitable for Passover, seek non-dairy substitutes or ingredients that are certified kosher for Passover.