Sayyiduna Abu al-Darda' (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Indeed, Allah Almighty has angels who descend every night and keep the dogs away from the animals of those fighting in His way, except for an animal that has a bell around its neck."
Al-Tabarani recorded it; its chain contains Layth bin Abi Sulaym, who is a mudallis, and the rest of its narrators are thiqat (trustworthy); some of them have been criticised in a way that does not negate their integrity ('adalah).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الجهاد / 9377