Had a major problem with rats in chicken coop. IN fact I set up an infrared camera right in the coop so I could watch on a monitor in the house. I was taken back by what I saw. When the sun went down, the rats cam out. Not one, two, three, five, ten, or even 20. As my chickens went to sleep on their perch(foot and half off the ground) countless rats ran around eating their food and drinking their water right underneath them. I tried Victor traps but it was slow going. I couldn't place the traps near the chickens, so the rats never came near the traps. THey stayed near the chicken food and water. They have poor eyesight but incredibly good ears. It was facinating to watch their movements and how they responded to any noises. Some rats were huge. Bottom line, I had to set out some poison in an area that the chickens or other animals could not get to. It was right underneath the rabbit hutch which the rats also liked to visit. In fact they would crawl right into the rabbit hutch. It looks like the poison has taken care of most but most likely there are a number of babies that were born in the burrows and will be surfacing soon. I did a lot of research on rat beaviors because of this infestation and has truly enlightened me.
Good luck with your rat hunting. Hope the spring traps work. I know poison is bad stuff, but when these rats multiply and you have 50 or 60 rats leaving droppings and urinating everywhere, you'll take drastic steps.