Sa'id (bin Abi Arubah) narrated it with the same chain, except that he said: The Prophet (peace and blessings be upon him) said: "When you are in the camel enclosures, do not pray, and if you are in the sheep pens, pray in them if you wish."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4353