Hello Everyone!

So, I have a 2010 male BP who only weighs about 400g. He is completely healthy, albeit a little on the small side. This I attribute to the fact that he is a hardcore mouser. I can not get this snake to switch to rats. I've tried scenting, but is there something else I can do? Both of my other snakes are on rats and are thriving. This guy's picky eating paired with the fact that I would really like him to gain some size and personally hate mice, are driving me nuts.

Any suggestions for a way to get my picky little mouser on to rats?