The bison kept everyone waiting. Despite being prodded by broomsticks, encouraged by large rattles shaken at them and hooted at by their handlers, many of the animals refused to scoot through the open rear doorway of one trailer, down the enclosed ramp and through the chute to the corral. By 11:30 p.m., the crew assigned to make that entry happen had departed, allowing an estimated 10 animals to exit when they were ready.