You should Always! pack them by hand. when using a grease gun to grease them you cannot inspect the bearings for any sign of failure. and it is very easy to over grease them and have the grease blow out all over the brakes.
Take them apart, clean and inspect the bearings, repack them and use a new grease seal.
The only thing the easy lube, ultra lube or whatever axles are good for are for boats. you can pump in new grease and push out any water contaminated grease. but even with that I would still take them apart at the end of every season to make sure there is no rust or damaged bearings!