In another post you said that your chameleon is about 6"...including the tail or not?
Most adult chameleons slow down a little during the cool seasons. Hatchlings wouldn't likely slow down, but as a chameleon nears his full growth, he should ease up on what he eats...and if that coincides with the onset of winter, it would make a difference.
5 crickets in 10 days is still low....even if he is nearly full grown and in the winter.
What are your cage temperatures? If he's too cool, he can't digest his food properly so he wouldn't eat as much.
How's his hydration? Some people say that sometimes a thirsty chameleon won't eat...but I've never noticed this.
Re: free ranging the crickets...the screen on my cages is fine enough that anything bigger than pinheads can't get out...so I simply throw in a few gutloaded dusted crickets every second or third day and they roam freely around the cage and in the plants and branches. Some will hide. I put a small container (jar lid)of greens, veggies and fruit in the cage so that the crickets remain somewhat gutloaded...and this brings them out of hiding too. You asked..."will the crickets harm my cham while he is asleep or is this just a myth?"...its not a myth....but it hasn't happened all that often in my experience. Although most of the time the chameleon will kick off the crickets, I have had some chew on the chameleon and cause damage. If you suspend one branch across the cage at the top so that nothing touches it, the chameleon can sleep there and the crickets won't be able to get at him. Of course, if all sides of your cage are mesh, this won't be possible since the crickets can (of course) climb the mesh and get to the branch.
Hoep this helps!