I don't know anything about tanning with eggs, I've only used brains, but I'm guessing you are tanning it with the hair on. There is a difference between cow hides and bull hides, the cows being somewhat easier to tan. Once you have the meat and membrane removed, you will need to thin the hip area quite a bit. If you have been tanning deer and elk, this will not tan the same way. Wes Housler made a video that really walks you through the process. I would highly recommend it. Larry Belitz also put out a buffalo tanning video. If you purchase one from Belitz, it is best used as a gag gift for someone you want to prank. Curtis