How much light are they getting? You are pretty far north and the days are still pretty short up there. They need about 15 hours of light to lay. If you are not doing so, you need to add artificial lighting. You say you had an egg-eater, so are some of them laying? What do you mean by "turned them out a week ago and gave them layer ration"? What were you doing before a week ago? If you recently made a change that is supposed to bring on egg laying, and assuming the change will work, it isn't going to happen overnight. It might take a few weeks to kick in.
What breeds are they? Some breeds take longer and lay less frequently than others, although 10 months should be long enough for any breed. Last question: Are you sure they are hens? Just kidding. I feel bad for you. I would be very frustrated.
Research all you kind find about laying hens and egg laying and make sure you are satisfying all the requirements, and don't overlook the lighting. I am guessing you got them in May and by the time they might normally begin to lay (Aug-Oct) the days were too short and are still too short, and they will start laying a few weeks after you add artificial light or when the days are at least 15 hours long. Don't give up.
Good luck.
UGCM