One year on an elk hunt 25 miles in the middle of the Selway wilderness we had some mules that decided chewing lead ropes was cool.
After rounding up the herd miles from camp a couple times we decided it wasn't cool so our brains went to work.
Best solution we came up with with our limited supplies was to put Tabasco sauce on the main offenders ropes.
Turns out mules like Tabasco.
We also realized that every time we touched the ropes the chit ended up in our eyes or on our sensitive areas.
Pretty hot stuff.

Since then I use a light weight chain while they are high lined.
Chew away fucktards.