I ship beef to family in the better grade picnic ice chests. I think the key is to turn the freezer temperature down real low for at least a few days before hand and then pack the cooler as full as you can. The beef acts like one solid ice block. I also tape all around the lid seal and steel band the top down with two steel bands. Ship UPS 2nd day saver rate and ship early in the week so it is not sitting in a truck or terminal over a weekend. The beef gets there reportedly as frozen as when it left.  

This is a good time of year to ship. Might be a bit riskier in the very hottest part of summer if there is any delay. If you keep the total weight down the rates are not too bad and it goes door to door rather than needing someone to pick it up at an airport. You want to make sure you have the right size cooler for the shipment so that the cooler is as full as possible but still close tightly. 

Heavy duty Styrofoam coolers and the matching size cardboard boxes would be less expensive and still probably work as well for less money if you have the volume to purchase in quantity. UPS does a good job with my coolers especially if you you mark whats inside and keep the weight down. Jim at Dawn