Discard any bruised or discolored portions of the fennel bulbs. Slice off 1/4 inch from the root ends. Stand the bulbs upright and slice them lengthwise 1/2 inch thick. Wash the fennel well in cold water.
Cook the fennel in 3 quarts of boiling water until the core is tender yet firm when prodded with a fork, about 7 minutes. Drain and let cool.
Beat the eggs in a small bowl and place the bread crumbs in a shallow plate. Dip the fennel in egg, letting the excess flow back into the bowl, then turn it in the bread crumbs, coating both sides. Press the bread crumbs onto each slice with your palm until your hand feels dry and the crumbs are sticking firmly.
Pour 1 1/2 inches of oil into a large skillet and set it over moderately high heat. Test the temperature by dipping in the edge of a slice of fennel; if it sizzles, the oil is ready.
Slip as many slices of fennel into the pan as will fit loosely without crowding. Cook over moderately high heat until a crisp, golden brown crust forms on one side, then turn and fry the other side. Using a slotted spoon or tongs, transfer the fennel to a wire rack set over a baking sheet to drain. Continue with the remaining fennel. Sprinkle with salt and serve immediately.