How does Crooks' room reveal he is animal-like, lonely and misunderstood?
The lengthy description of Crooks' room at the beginning of Chapter 4 tells a lot about his situation as the only black man on the ranch. It is not really his own private room but described as the harness room. It is a lean-to shed attached to the barn. The room is full of leather trappings worn by the horses. Evidently a big part of Crooks' job on the ranch is keeping all this leather paraphernalia in repair. He is accommodated about as well as the horses and mules. His bunk is a long box filled with straw. He has no sheets. He has a few old books and magazines. He does a lot of reading because he has to spend most of his time alone. He apparently does not have a radio. Television, of course, did not exist in those days; it came out after World War II ended in 1945.
The other men won't allow him to come into the bunkhouse. He is naturally very lonely. He confesses as much to Lennie when the big man intrudes. Crooks is only animal-like in that he has more interactions with the horses and mules than with his fellow humans. He is misunderstood in the sense that people believe he is misanthropic and prefers to be alone, when he really would like very much to be able to associate with the other men but has no choice in the matter. He is naturally somewhat angry and defensive. His pride is his only solace.
He is probably right in trying to defend his privacy. When three lonely people--Lennie, Candy, and Curley's wife--all congregate in his room they create danger and disorder. Crooks knows that his position on the ranch is precarious because of his severe physical impairment. The invaders only remind him that he is better off alone in this tiny sanctuary off the barn.