You know these kids are straight; them an' their ol' man's come to work th' Range for wild ones on Rennie's own askin'.
Rennie did not want the kids' father working for him.  
mnli hypothesis: Rennie did not want the kids' father working for him.   premise: You know these kids are straight; them an' their ol' man's come to work th' Range for wild ones on Rennie's own askin'.