Why is it that it's recommended to throw eggs away?
There is residue from the wormer in the eggs. Eggs should not be fed back to chickens as the residue will help build worm resistance to the wormer the next time it's used possibly making the wormer ineffective or requiring a higher dosing. It may also extend the withdrawal period. This is also true for antibiotics.
Also it's possible that a person may be sensitive to the residue and may have an adverse reaction.