yes, I agree, you can't make a timeline that fits both the film and the short story. the film makes some departures in the timeline of the short story. for example, I am convinced that because of the date shown in the film when Jack competes in the rodeo in Childress, and the date shown on the post card sent to Ennis later, that Bobby can't be Jack's child. But, the short story has no such implications.
I agree, Brokeplex, that it is only in the movie and not the short story that the possibility that Jack is not Bobby's biological father is raised. But I was wondering if those who have been members of this board for much longer than I could tell me if the "Bobby the bastard" theory has been discussed here before? If not, maybe it deserves a thread of its own. However, for the time being, here are the theory's essentials. It's all to do with dates:
1. The fireworks scene takes place on July 4, 1966. We know this because the announcer tells us that it is July 4, 1966.
2. The next scene is when Jack meets Lureen for the first time. A banner below the judges' box reads "CHILDRESS COUNTY FAIR AND RODEO" "4th ANNUAL" "AUG 7 RODEO AUG 14". Although the year isn't given, it also has to be 1966 as the reunion scene, when Jack is married to Lureen, will take place just a year after this scene.
3. The reunion scene takes place on Sept. 24, 1967. This is clearly established both by the content of the postcard and the postcard's datestamp.
5. During this scene, Jack tells Alma and Ennis that he is the father of a kid who is eight months old.
6. That means that Bobby must have been born in the January of that year.
7. But Jack had only met Lureen in the August of the previous year, so, even if he had impregnated Lureen that night, Lureen wouldn't be giving birth to a perfectly normal and healthy boy - as from all appearances Bobby is - some five months later.
8. Therefore Lureen must have been pregnant when Jack first meets her and Jack is not Bobby's biological father.