I don’t use hormone implants, nor do I see vets for my chickens. Your hen is 3 years, and some hens may stop by then. I have had a few lay until 6 or 7, but not too many. It is up to you whether or not to get the hormone implant. It might allow her to stop laying altogether, if she is laying internally. But it is awfully expensive to do that for a hen, especially if you are going to consider doing that for all hens. I prefer to let them live as normal a live as possible. I will use an antibiotic if I know what is wrong or suspect internal laying or reproductive infection. Many develop crop problems. But I just do so much. If they are not getting better, enjoying life or suffering, I will put one down. The I will do a necropsy to look for what was going on.