We put some 90 weight motor oil in our sitting Buckeye hen's nest box as a prevention for mites because our flock of bantums had mites. The oil smelled pretty strong. Our eggs were due to hatch, and never did. We cracked the eggs open and though the chicks were pretty far along, they were dead and stank. The oil never came in contact with the eggs, but was 2 or 3 inches under the straw. Could the fumes of the oil have killed them or effected in the egg?