Are you sure they are yearlings? That's awful small, considering they hatchout at that size

. If they are indeed yearlings, I would be very weary about them. My 8 month old female is 31", and my yearling male, pictured below, (albeit he is large for his age) is 3.5' and feeding on one rat every 2 weeks...
<img src="http://www.ssnakess.com/photopost/data/513/22darkygrow2.jpg">