One of the unanswered questions in "Where the Red Fern Grows" relates to why Grandpa signed Billy up for the contest. If Billy won the hunting contest with his dogs, he would win enough money to save Grandpa's store. However, the text is unclear about whether Grandpa signed Billy up for the competition for his own gain or to support Billy in some way.
Other unanswered questions have to do with Billy's character. When dealing with Rubin Pritchard, Billy is shown to be very fair. However, Billy also needlessly exposes others to danger as he hunts for his dogs during a storm. These situations contrast each other and leave parts of Billy's character open to speculation.
However, Rubin's motivations and character are also open to speculation. Near the end of the novel, Rubin accidentally trips on an ax, and as a result, he helps to kill Billy's dogs. However, it is unclear whether or not he would have killed them anyway. The reader is left wondering if Rubin is truly malicious or just a victim of circumstances.
Other questions that are left unanswered have to do with whether or not Billy gets new dogs, goes to school or actually saves Grandfather's store.