Northern Pine not feeding????

Hi,
I have a male Northern Pine snake he is about 14months old, and as never missed a feed since I bought him (12 months ago) One day when he was feeding (about 6 weeks ago) he ate the first weaner no problem then started on the second but spat it out, since then he as stopped feeding all together he wont except any food at all. weaners, mice, rat pups, pinkies etc, He dosent seem to have any kind of feeding response. He is very active and not showing any signs of being lathargic
The only change I have made to the vivs is to run them on a stat, the temps in all vivs are perfect, Warm area 80/82 Cool area 75/78.
All my other snakes are feeding without problems, and they are running on the same stat
Would really appreciate some advice on this if anybody as any to give.
Thanks

A couple of thoughts. Have you had a fecal test done? May have parasites. A trick I use is to brown bag the snakes with their food. Hoppers are crazy little things, I would suggest putting the snake in a brown bag with a hopper mouse. If you are concerned about the mouse chewing on the snake add a little mouse feed in also. Find the wildest craziest hopper mouse you can, put them in the bag and the mouse will annoy the snake so the snake will kill the mouse. Usually while coiled this will trigger a feeding response and the snake will eat.

Another idea is to use a different food item. Pine snakes eat birds and eggs. You can buy frozen chicks and scent the mouse with it, you may even need to wash the mouse too.

Good luck, hopefull others will be able to give you better answers and ask you better questions.