It is mentioned in numerous Hadiths by Ja'far al-Sadiq that it is permissible to make wudu with water that is not overwhelmed with the smell of dead animals. If there is a dead animal, it is recommended to take wudu from the opposite side of the location of the animal. He also said it is permissible to take wudu from the ponds between Mecca and Medina in which people perform ghusl, dogs and beasts drink, and animals die so long as the water level is at least up to the knees.