Yes, your beardie sounds a bit on the small side. When I got my beardie, I was told he was 4 months old, and he was 13 inches long. I know there are several members of this board who have 4 month old beardies that are upwards of 16 inches :shock: and eat more than 100 crickets a day. There is a beardie named Toothless who was almost 19 inches before he was five months old (
viewtopic.php?f=49&t=173042)! But no two beardies are exactly the same. As long as he's eating and growing, and you have the proper
UVB light, etc, then you shouldn't have to worry. It's a good idea to regularly weigh and measure him and keep track in a notebook, so that you can tell how well he's growing. I actually keep track of everything from how much my beardie eats, to how often he poops, gets a
bath, etc. If your beardie isn't growing well, you may want to have a fecal exam done to make sure he doesn't have parasites. 100+ crickets in two days sounds like he has a pretty good appetite, so if he's not growing, it may be because of parasites. Also, I've always heard that at that age they should have 1 feeding dusted per day with calcium 5 days a week, and multivitamin the other 2 days.
And for your original question, I agree with everyone else that it is definitely not worth the risks to house the two of them together.