Would the film crew be zombies as well, or do they have specific no-eat clauses in the contract?
What would them being technically dead entail? Decaying limbs? Some extra strength?
For that to work, the zombies would need to talk more than just grunting. Subtitles would get annoying very quickly. Maybe the documentary crew could have some Google Translate thingy to accommodate this? Maybe less talking and more showing could be what makes this a hit?
Sounds similar to my idea, though I don’t know whether 10h at 65°C would yield the same result as less time at 100°C. Printing such a box with PC or ABS would allow higher temperatures I think.
Have you tried adding a brim or mouse ears to remove later?