Musnad Ahmad 658:71

Abu Mu'awiyah narrated to us, Al-A'mash narrated to us, from Abdullah ibn Abdullah, from Abd al-Rahman ibn Abi Layla, from Al-Bara' ibn Azib, who said: The Messenger of Allah, peace and blessings of Allah be upon him, was asked about performing ablution (wudu) after eating camel meat, and he said: "Perform ablution from it." He said: And he was asked about praying in the resting places of camels, and he said: "Do not pray in them, for they are from the devils." And he was asked about praying in the sheepfolds, and he said: "Pray in them, for they are a blessing."