How big are these snakes that are not eating? If they are adults then I wouldnt worry to much about it. If heat,humidity and all the rest of that is good. They might just have breeding on their mind. I had a baby that didnt start eating for 4 months and hes fine now. I too tried everything and nothing worked. He ate when he was ready. Also had an adult female go off food for almost a year. One day short of being a year. She ate when she was ready.

As long as they look good dont look to skinny or sick looking just keep trying once a week. If you want you could take them to a vet to see if they are sick or something. My oldest male only eats a large rat once every 2 months. I try to feed him every week he just doesnt eat. He doesnt look skinny or sick looking hes 17 years old. I got him in 93 and he was atleast 2 years old when I got him. Like said if they look ok just stay at it try once a week. Try not to bother them to much. If they are not sick or anything they should eat when they are ready.