What is the identity of these images that appear in the Willy Wonka tunnel scene?

So in the 1971 Willy Wonka movie there's the infamous tunnel scene where scary images appear and it's true meaning isn't revealed. But what I'm interested to know about is the origins behind these. These days there's so many people searching for origins behind things like cursed images and liminal spaces so that brings me here. There's also the celebrity no 6 sub I may bring this too.

So first, one snippet of footage shows a millipede crawling over a sleeping guy's face which I've found is a writer Walon Greene. Another shows Slugworth. But the others I'm interested to know more about.

One shows a close up of someone's eye, but who's eye does it belong to?

One shows a Jackson's chamleon eating something, is this footage stock footage online somewhere or not?

Another shows a chicken having it's head chopped off, again is this footage anywhere outside the movie? Who is chopping the head off?

And there's a close up of a scorpion's mouth and some creepy-crawly I can't figure out like it looks like a centipede but also like a velvet worm.