Bearded Dragon color changing

Question
hi, thanks for your time. I have a baby bearded dragon about 1-2 months old, and another baby bearded dragon about 2-3 months old(seperate enclosures). im a first time owner but think i know alot about them. Now to the question, the youngest one seems to change color when i put him in his enclosure, he's a light tan color but when he's in there he turns really dark(his whole body) and has dark spots on his belly(i'll provide a picture). i do have a UVA and UVB lights provided for both and set on timers for 12s hours everyday and there not Reptiglow, there seperate lights the UVB is a tube both 5.0Reptisuns and not sure what the name of the basking bulbs are but i think by ZooMed.i dont see any signs of stress from the younger one and dont see why he would be stress i evevn put paper on the glass so nothing distracts him. Oh and fyi the 5.0 Reptisuns are at least 8-11 inches from them.i dont have any waterbowls in there but i do hydrate them every day with drops of water and they both drink and i feed them crickets with calcium supplemt 2-3 times a day and the crickets arent fed bigger then the space between there eyes. Basicly i would like to know why his skin changes color becuase some say because of stress and some say because there shedding but no definate answers and since hes still a baby i worry about the little things lol. Also the enclosures are not to big for them.Sorry for the long letter but i appreciate your time, thank you!

Answer
 Beardies will also darken to absorb more heat and UVB, so it may not be stress, just that this baby wants to be warmer than the other. You might want to consider getting a Reptisun 10.0 tube to increase UVB and a slightly higher wattage bulb for warmth. You don't mention a good salad, only insects.  Beardie babies should be eating a good finely chopped wet salad of calcium rich greens every day.  Collards, mustard greens, dandelions and turnip tops are good greens.  Stay away from lettuces, they are poor nutrition.