Sweeping Edge enchantment not working for foxes

When a fox picks up a sword with Sweeping Edge, the enchantment has no affect when attacking chickens or rabbits.

What I expected to happen was...:
All mobs around the target to take damage.

What actually happened was...:
Only the target took damage.

Steps to Reproduce:
1. Give a fox a Sweeping Edge sword.
2. Drop the fox into a pen full of chickens or rabbits.