My word, at a year old he should be eating much larger prey. Adult mice at the very least, or a similar sized rat. His prey is far too small, which undoubtedly means he is underfed and very small himself. Don't change prey size dramatically, but please try and get him eating larger meals.

My seldom fail method of feeding F/T, until my collection got too large and made raising my own food the logical choice for me, was this:

Thaw the selected prey item at room temperature for several hours. It should feel soft and limber with no hard spots inside. Dunk it in hot tap water, the hottest your sink will provide. Bring the prey, still submersed in water, into the room where your snake is. Open the enclosure and remove the hide or hides, then close it. Remove the prey from the water and towel it dry with an old rag. Lay the damp rag down on a flat surface and lay the now damp prey on the rag. Get your hairdryer ready, and start blow-drying the prey, aiming the warm, rodent scented breezes towards the enclosure. Pick the prey up and make sure it is warm and dry and fluffy all over. Now, get your feeding tongs and grip the prey by the scruff just above the shoulders. Aim the hairdryer at the head, and give it 15 or 20 seconds to get the head super hot. Quickly switch off the hairdryer, set it down, open the enclosure with your free hand, and offer the prey. Try not to drop it on the snakes head, unless by now he's actively hunting for it and tries to snatch it out of your hand. If he's interested but still suspicious, offer it in the corner nearest him without being on top of him. Give him a few seconds, if he doesn't strike, GENTLY wiggle the prey just above the bedding. You want to entice him, not scare him. If he still doesn't take the bait, drop the prey where it is, close the enclosure and walk away. Darken the room if you can. Leave him alone for at least 30 minutes. I mean stay out of the room completely. Then it's okay to check if he's decided he wants it. If he hasn't touched it, you can try heating the head one more time and offering it again, with a little more wiggle than before.

Some snakes are simply dead set on not eating F/T, I have a few like that. If it is really an issue to get him food in the proper size each week, and he steadfastly refuses f/t, it may be time to let him go and find one who readily accepts f/t.

Gale