Could my Iguanas growth be stunted?

I got my iguana about 2 years ago. He is now 3 or 4 years old. The problem is that he is only about 2 1/2 foot long. He hasn't grown any sense i have had him, and i haven't actually been keeping him fed right or in the correct tempature. I just built and outdoor cage though, and sense this, it has became bright orange instead of its usual greenish grey coloration and is a lot more muscular.And it does eat right now and is always in perfect temperature.. Yet the length hasn't change? Has it stopped growing?