We are not entirely sure but it seems to be the most likely scenario. Only alternatives are that one of our geese killed them or that a snake came in, but I found no snakebites on the dead chickens nor are any of the eggs missing.
I made another topic about the matter with some pictures of the dead Chickens, which look like they're pecked to death.
https://www.backyardchickens.com/th...-are-killing-eachother.1386668/#post-22770843
I am not familiar with the predators in your area, but this looks like snake damage, to me.
There are two kinds of snakes, those that kill with venom, in which case you may find a bite mark on the victim; and constrictors, who kill by wrapping themselves around the victim and squeezing. In the case of constrictors, you won't find bite marks, but you will often find that the neck is broken and floppy.
To me the photos you provided in your other thread look like chickens killed by a snake, and then the snake started to swallow them head first. The chicken's head and neck looks quite damp, and the damage to the head looks more like digestive juice damage than pecking. Some snakes don't have a good idea of how much they can swallow, and will try to swallow birds that are too large for them to actually get down.
Snakes are also drawn by eggs, which are very easy for a snake to eat. Typically the snake will disgorge the eggshell, whick will look crumpled like a wad of paper. You may not find this crumpled shell near the nest because the snake may leave to find a safer area to digest the egg. If a hen challenges him, or is sitting on eggs he wants to eat, the snake may then attack the hen. I have lost both hens and roosters to snakes.
Where I live in Missouri, USA, the constrictor snakes don't grow large enough to eat an entire chicken, but they will sometimes try a couple of times before they give up. Then they just kill the chicken, if it gets in their way, and eat the eggs. I usually have to find the snake and kill or re-home it, to stop the damage.
For a hen who is setting or who has young chicks, or for smaller birds, I put them in welded wire pens where the mesh is too small for a snake to get through, something like 1 inch by 1/2 inch welded wire. The pen includes a floor of the same wire, so the snake cannot come up from the bottom. This excludes large snakes that would be attracted to eggs or young chicks, and also some of our other local predators.
I hope this helps.
