Kevin Kunkel was auditioning for the film "Nebraska" (a role he eventually landed) and needed to be clean shaven. This had an impact on the ending of Death Rot.
The barn featured in the film was listed on the property description as the second largest barn in South Dakota.
The short film "Eternal Beauty" (seen on the drive-in screen at the beginning) was created as a test using most of the same cast and crew.
The police were called when the farm owner stumbled upon the butcher room. He thought production had wrapped and was surprised by the realism.
The band Tennessee Murder Club are the real performers of the music in the opening of the movie.