Sometimes you can find Bison by themselves which has happened to me a few times and you can make a trap for the single bison by getting 10 high door frame and 4 foundations and putting them into a 2 x 3 rectangular box and putting the foundations in the 4 corners of this trap and leaving one side open That only has two walls and luring the bison in with a flyer by going over top of the trap and making them go into the trap then close off the open wall and then you can take out the bison and feed it, rockcarrots then you will have a bison.