"Maybe we can ride night herd.
It'll be great fun." Riding night herd was not Injun's idea of fun, but he was so glad to be with Whitey again that he made no objection.

He seldom made objections, anyway.

It occurred to neither of the boys that after Injun's long pursuit of the horse-thief, it would be a hardship for him to ride all that day and possibly that night.

And, of course, Injun wasn't hungry.
He had not been fool enough to start out on a long chase without providing himself with food.
So the boys rode on.

Even had they known into what they were riding it is unlikely that they would have turned back.