Minecraft wiki entry for Stray, associated text: 0–2 bones. The maximum drop is increased by 1 per level of Looting, for a maximum of 0-5 bones with Looting III.
0–2 arrows. The maximum drop is increased by 1 per level of Looting, for a maximum of 0-5 arrows with Looting III.
0–1 arrow of Slowness (if stray was killed by the Player or tamed wolf). Each level of Looting increases the chance of this drop by 50% of the previous chance, resulting in a maximum of 93.75% with Looting III.
Any picked-up equipment has a 100% chance of dropping and drops with the same damage level it had when picked up.
Any naturally spawned equipment (including the bow) has an 8.5% chance of dropping (9.5% with Looting I, 10.5% with Looting II and 11.5% with Looting III). It is usually badly damaged and has a chance of being enchanted.
Strays drop 5 when killed by a player or tamed wolf, and an extra 1–3, if the stray has equipment.