Growing up in a farming community, death was common and not hidden from children. The more horrific thing for me as a kid was discovering:

"Today’s domesticated turkeys are anatomically manipulated to be so heavy and large breasted, because breast meat is the most desirable and therefore commands the best price, that they are now incapable of breeding naturally."

So, there are people who have to perform this artificially for the males and then for the females. In fact, since turkeys are now raised in mega-farms, there are people with this as their career.

Responding to half your post, there are cultures (such as farms) where death is dealt with more frankly, and it doesn't seem to cause harm to children outside of making them more practical.

One time I called my friend with some land in Texas, his 7 year old daughter picked up the phone. I asked "Can I speak with you Dad?", She said "sure he is feeding the chickens". I asked, "Do you name the chickens?". She replied "No, because we eat them, they taste good". Very innocent, cute response, from a very well adjusted kid.

My inlaws once raised a couple of turkeys. They did name them. Thanksgiving and Christmas. They tasted good.

I think the key is that it's the parents who are uncomfortable with death, since they don't have to deal with it on a daily basis, either.

Watch and enjoy:

http://www.findinternettv.com/Video,item,1838332278.aspx

Perhaps because children tend to assume animals are a lot smarter than they actually are (I remember that I used to), and that their experiences are more equivalent to human experiences.

I wonder whether this is natural, or whether it comes from the fact that children spend all their time watching movies and reading books about intelligent anthropomorphic animals.

I think children tend to project their own concept of being alive onto other creatures. Basically, they assume the turkey is, in some way, like them.

While I think a turkey clearly does not have the same understanding of mortality that we do, I also think that they clearly don't want to die. Basic survival is a common trait of any successful species. The concept of want is different, though, since they have a much more primitive type of consciousness.