I've shipped lots of shrimp in breather bags. I've had a couple leak, but other than that they are great. If you double knot the top of the bag and give it a good squeeze before boxing it up, they should do well.
That's all I use. They are great. Just get all the air out. I start by bringing the top togther where there is still some water so I know all the air is out. That helps the bags from leaking. I've taken breather bags and dropped them from 6 feet and they still don't bust Thay also make great water balloons but way to expensive for water ballons