Chapter 305 Section 3
A donkey cannot go out with a metal bridle as it is more then is required for
purposes of monitoring.
Chapter 305 Section 4
If this specific animal needs more monitoring even though this species
normally doesn’t need as much, this animal is permitted to carry something
which monitors it better.
Chapter 305 Section 5
An animal which normally wears a collar can wear
it on Shabbos outside.