Sayyiduna Abdullah bin Mughaffal (may Allah be pleased with him) narrated from the Prophet (peace and blessings be upon him): "When you come to the camel enclosures, do not pray in them, and when you come to the sheep pens, pray in them if you wish."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4352