I noticed that, too. I wish I hadn't waited so long to try it. But... it was new... and we always did it the other way...I never used a heat lamp, went right to the MHP with my first bunch. What I did notice is that mine were feathered more than photos of chicks of the same age raised under a heat lamp. At 5 weeks, my CornishX are completely feathered except for a little on their heads.
