I think that is too much space for a hatchling...baby ackies are just *so* little, and the last thing you want to do is start him off @ a disadvantage.

Can you partition off the enclosure to make it 3' long instead of 5' long until he grows up some? This would allow you to still provide a range of temperatures necessary for basking/cooling, without making the overall space too overwhelming.

Good luck!

K~