Peace be upon you. Why aren't chicken eggs washed before cooking?

There is no harm in washing chicken eggs before cooking them for cleanliness, but it is not obligatory because the moisture on them is pure according to the majority of scholars, especially if the chicken's feed is pure. As Ibn Farhun said: "One is commanded to wash eggs before breaking them, but if they are not washed, there is no harm." They commanded washing them due to the possibility that they might come from a jallalah hen (one that eats filth).