Dissolve the yeast into the water. Add the salt and fennel seeds. Mix enough flour into the water to make a stiff dough. Start with 10 cups, and add a little extra if needed. It should be very firm, much harder than bread dough. Work the dough till smooth, then cover with plastic, and let stand for 1 hour. Preheat oven to 350 degrees F. Cut dough into pieces, then roll out each piece into a rope, about the thickness of your finger. Form into a doughnut like shape. Boil water in a wide pot, then drop 3 or 4 doughnuts into the water at a time. When they rise to the top, remove and place on towels to dry, about 5 minutes. Place on baking sheets, and bake 30 to 45 minutes, or till golden. Remove, and cool.
(Makes About 4 Dozen Depending On Size)