Hi there....he is a bit on the slim side, but he does have a nice thick tail base. You might want to get him to about 375 -425, but not much more than that. His build is more of a slim dragon rather than a stocky one.
He looks very active, is he ? He's not unhealthy looking, just like slim people are not unhealthy. If you haven't had a fecal test done, though you might do that to check for parasites.
Yeah he's pretty active. Some days he lounges in his viv all day and other days his running around in it. When I get him out of the viv though and he's on the floor he runs and explores a lot.
My concern is that some days he eats a lot others not at all. He is eating super worms right now cause he had an aversion to crickets but I am going to try crickets again. My other concern is that sometimes when I pick him up his stomach seems super empty and skinny.
I've seen thinner beardies in the wild (I live in Australia and sometimes take long 4x4 road camping and fishing trips and often see beardies along the tracks, on tree stumps, on termite mounds, on weathered fence posts.
Superworms are OK, but I think he'd benefit if you got him onto Herpaboost and silkworms.
Are his poos nice and moist ? he might be a bit dehydrated.
Odd , that he isn't keen on silkworms - all my beardies and bluetongues love them and make them disappear almost instantly with very little need for encouragement when I've been raising silkworms (I raise mine from eggs on silkworm chow and or fresh mulberry leafs) specifically for my lizards.
Eggs should be a lot easier to find (and cheaper) than silkworms are (least they are here).
If you buy silkworms as eggs, you'll have worms big enough to be worth using as a prey insects for him (about 1" long or bigger) in about 6 weeks , you can buy canned silkworms (cooked pupae) too, I've never been able to convince my skinks or beardies to eat them (voluntarily) but they are a possible alternative food.
You might need to hand feed the silkworms (raised on mulberry leafs or Silkworm Chow), superworms (fed wheatbran and oatbran mix, I give my supers freshly dead crickets and carrot and stale adult beardie pellets as well) and Ca dusted gutloaded crickets(I gutload my crickets with carrot, pok choi greens and adult beardie pellets) to him if he's not interested enough in them to eat unassisted.
Have you tried hand feeding him ? this way you can be sure he's getting plenty of high quality live prey insects in his diet in order to build him back up.
This is where I buy my Herpaboost http://www.vetnpetdirect.com.au/vetafarm_herpaboost#.VZAcurkViw0 ,
you can probably buy it over there too , it's highly recommended by reptile vets and good breeders for assisting sick or malnarished reptiles and I personally keep 2x 100ml bottles in the fridge in case I ever need it for a rescue or if one of my skinks or beardies becomes ill.
Another product worth trying him on is Wombaroo Reptile Suppliment http://www.vetnpetdirect.com.au/Wombaroo_Reptile_Supplement#.VZAfF7kViw0
(also recommended as good intensive care food for lizards by my reptile vet (I've a 1kg packet in my pantry that I bought in case I ever need it - is a powder that you mix with water and make into pellets or a slurry as needed)).Again you can probably buy it over there and it's highly recommended. Some people use it as supplement for their females and their hatchies to built them up along as the regular prey insects (including silkworms) and greens and veg and pellet type foods).
I've heard of Reptile Intensive Care too, which may helpful.
Beardies are omnivore-insectivores (vegetables/fruits/green leafy plants + insects) so poutry and egg products are not really suitable (this is what I was told by the my reptile vet (who also works at the Gosford Reptile Park). Beardies are not adapted to cope with digesting poulty and egg products. I suspect Carnivore Intensive Care (Oxo prod ?) , just looking at the very high animal fat levels in it along with the very poor Ca/P ratio in it http://www.oxbowanimalhealth.com/products/type/detail?object=1609 indicates it is not a good choice, a better choice might be Herbivore Intensive Care supplemented with silkworms.
(http://www.oxbowanimalhealth.com/products/type/detail?object=1558 , the fat level and Ca/P are much better).
The proteins found in prey insects such as superworms, mealworms, silkworms, gents, crickets, roaches are very different to those found in poultry and egg products. (Lean poutry and egg are at best a very occasional treat for reptiles like bearded dragons.)
IMO if a vet sold you Carnivore Intensive Care to help build up your beardie - he's incompetent and long term use would probably lead to fatty liver desease (from excessive animal fat intake from his diet) and MBD (from the very low Ca/P ratio in it, phosphorus interfers with Ca metabolism).