I have a large area, fenced in, with a coop inside it . I do not lock coop at night,chickens can go into fenced in area as they want. There is something digging under leaving a golf ball size tunnel. I did find a dead mole in fenced area days ago, a very small one. Chickens killed it. Im ,not sure what is doing this or how to stop it. Might be a rat wanting chicken food. Will a rat leave this type tunnel? and will they do any other harm,,,like hurting chickens or eggs??? Got my first egg today,,BTW. Have chicken wire buried at about 6" all the way around. If a rat,,,how can I stop this???