A fact I also pointed out on the old board. Feathers are anhydrous keratin scaffolds. They can't even dehydrate at 200 degrees!
I also find it odd that he would think feathers should spontaneously combust in seconds at temperatures significantly lower than those used to cook most foods....
I can testify from personal experience that a person can tolerate a 200
o environment with no special protection, at least for relatively brief periods.
In my youth I worked in a textile factory where part of the weekly routine was cleaning the huge dryers we used. Each one was a steel box about 50m long, perhaps 4m wide and high; upholstery went through it on sort of a conveyor belt arrangement. They normally operated at about 370
o F; once a week they were shut down for cleaning and once they were cooled down to 200
o, the younger employees went inside to clean the "flock" (accumulated lint) off the filters. Obviously you didn't want to overexert yourself, and you were careful not to touch any metal surfaces with a bare hand, but otherwise it was quite tolerable for the 15-20 minutes you were inside at a time.
OSHA probably requires more stringent safety procedures these days, but 40 years ago no one thought anything of it.