I went to the cave that has a lot of Ferox and some Polar Bears, after getting rid of the Polar Bears I was being followed by 4 or 5 Ferox. I decided to tame them before the berry exploit was fixed I knocked two of them down and as I start to go for the 3rd one he transforms I was dumbfounded and tried to run for my life I got wrecked and lost my stuff.
First of all, keep him out of the light, he hates bright light, especially sunlight, it'll kill him. Second, don't give him any water, not even to drink. But the most important rule, the rule you can never forget, no matter how much he cries, no matter how much he begs, never feed him after midnight.
Built a pen to lure and trap a 150 ferox using bloodstalker, worked fine. At the 50% mark ferox duplicated into two extra ferox for a total 50% done on each one ended up with 3 max level triplets. But level did not increase after taming until i cryopod the feroxes