Suspicious Lost Dog In Salisbury: UPDATE

This morning at 6:30 the two dogs in the picture went outside for their morning run. At 6:35 the St. Bernard returned without the other dog. She was gagging and drooling and shaking badly. I got her in and then started looking for the other dog. Her name is Tess. I called for a couple minutes and she didn't show up. Within minutes I was in the car and drove down the road a bit to where a dead deer had been in the field. Thinking maybe she was trying to drag some of the deer back to the farm. She still hadn't returned. We have been looking for her all day and nothing. What we did find was the second picture of chicken on my property. I am now concerned that my dogs were lured to the road and in an attempt to take them, the one got away. She is so traumatized that she won't move. We are still waiting to see if she is going to show any signs of poisoning. The Shepard still has not been found and there are no signs of her or that she would have ran. Someone said you sometimes post stories of lost dogs.