Most chains on a hitch are usually over kill. Mine came with 3/8" grade 70 transport chain and a grade 70 grab hook like the picture above.
Mine are always twisted on my bumper pull trailers. I don't cut my chains to a certain length as I use different trucks with different type hitch/ball placements.
No more weight (500-1500 lbs) than the chain is carrying on a unhitched trailer its not going to break with twisted chains. Now if the OEM chains were undersized or owner replaced the chains with a cheaper lower grade 40 chain and a smaller diameter then its possible a chain can be broke from a break away condition.