What would leave behind 2 bodies?

[The Moonshiner]

That's a snake.
I deal with it every year and have seen it too many times.
It is from unsuccessfully getting past the shoulders. Ive dealt with a lot of predators and nothing leaves a bird like that from my experiences except a snake.

 

[Sonya9]

Snake. Looks like the snake tried to swallow the chick head first but couldn't get its mouth past the shoulders.

Odd that it would be carried outside the coop though.

Op you need to find and seal up any openings in the hen henhouse. pay special attention around the door. If you have a dirt floor then get some chicken wire or hardware cloth and create a apron as the snakes WILL be back and in many areas a chicken coop will attract a fairly large population so killing one doesn't help (and very well may not be the same snake). As long as the birds are in a snake proof hen house at night they will be fine, attacks don't happen during the day.

 

[Weeg]

I am now thinking snake too. I’de put out a live trap out but I don’t know what you would use to bait it. Maybe the dead chicks it left behind?