Wheel bearings

I must be unlucky. I purchased my Open Range new in 2014 and didn't check anything and had no issues the first year. Last spring I noticed a little grease splatter on a wheel so I decided to check and had a seal had failed allowing grease to pass, replace seal and repack and also did the other wheel same side, no issues on that one. One trip later I was parking it and noticed one hub warmer than the other 3, Temp check showed 141 deg and others were around 118 deg. Pulled it and another seal had failed, caught it in time, clean up replace. This season no trips yet, I knew I had to do one wheel from the factory, same thing, no grease splatter on the wheel but the seal had allowed grease to pass and coat shoes. No idea what caused all this or if it's normal. I have the zerk fitting but have never used or would I use it.