Musannaf Ibn Abi Shayba 35:10

Zayd ibn al-Hubab narrated to us, from Abd al-Malik ibn al-Rabi’ ibn Sabra, from his father, from his grandfather, that the Prophet (peace and blessings of Allah be upon him) said: "Do not pray in the resting places of camels." And he mentioned that Abu Hanifa said: "There is no harm in that."