Crooks is a stable buck, meaning he takes care of the horses and associated beasts of burden. This is an area where he has an acknowledged level of expertise. Because the work is not seasonal, he is a permanent resident at the ranch and has accumulated more possessions than the other ranch hands.
Some of the other men also admire Crooks for being educated and reading. Candy says he is a "nice fella" and that
He reads a lot. Got books in his room.
Crooks is also good at repair work. He has three damaged harnesses hanging in his room that he is working on. He is good with leather and has quite a number of specialized tools to work with.
Finally, Crooks is a good fighter despite his crooked back. The Christmas before, he brought a gallon of whiskey to the bunkhouse for the men. Though he is usually banned from that location, the men let him stay. One skinner named Smitty took after him, and the men arranged for a fight. Because Crooks has a bad back, Smitty was not able to use his feet. Crooks won the battle.
In fact, it seems that the only mark against Crooks in the other men's eyes is his race. He is good with animals, good with repair work, good with leatherworking, a good fighter, and a reader. It is ironic that none of that counts as much as the color of his skin.