why was it particularly difficult to be the slace in charge of colonel lloyd horses

Colonel Lloyd's horses were his pride and joy. He expected no less than perfection from those who cared for them.

"...in nothing was Colonel Lloyd more particular than in the management of his horses. The slightest inattention to these was unpardonable, and was visited upon those, under whose care they were placed, with the severest punishment; no excuse could shield them, if the colonel only suspected any want of attention to his horses—a supposition which he frequently indulged, and one which, of course, made the office of old and young Barney a very trying one. They never knew when they were safe from punishment. They were

frequently whipped when least deserving, and escaped whipping when most deserving it. Every thing depended upon the looks of the horses, and the state of Colonel Lloyd’s own mind when his horses were brought to him for use. If a horse did not move fast enough, or hold his head high enough, it was owing to some fault of his keepers."