Make the chicken stock: Place the chicken, parsley and salt in a pot and cover the pot ¾ the way with water. Place over high heat and bring to a boil. Reduce the heat to a gentle simmer and continue cooking the broth for 1 ½ to 2 hours, skimming any impurities that reach the surface occasionally. Strain the broth through a sieve and transfer it into a clean pot. Keep the broth warm over low heat. Set the chicken aside and discard the parsley. 

Place 4 quarts of water into a seperate large pot and bring to a boil over high heat. Reduce the temperature to keep a simmer and cover with a lid.

Make the matzo balls: Mix the matzo meal, eggs, chicken fat, salt, pepper, parsley, cumin and sparkling water in a bowl until combined well. Cover the mix with plastic wrap and set it aside for 30 minutes.

Scoop a generous tablespoon of the mixture and roll it into a golf size ball between the palm of your hands and place into the simmering water. Continue shaping the matzo balls and placing them into the water. If the matzo mix sticks to your hands, dip your hands into water to prevent sticking. Once all the matzo balls are in the simmering water, place a lid on the pot and cook for about 45 minutes until the matzo balls are cooked through and fluffy. 

For each serving place 2 matzo balls in a bowl with a few ladles of chicken stock and serve hot.