Possible MBD in my Chameleon

Question
QUESTION: I have an adult male yemen chameleon. Recently i have noticed his back end seems to touch the ground when walking. After researching i am thinking this could be early symptoms of MBD? He has a uvb bulb in his viv and does like to bask i am also dusting his locusts with calcium w/o D3 and gut loading them with a grub and lettuce and carrot. Is there anything else i can be doing. I've just ordered a portable openair viv so i can have him out in the sunshine as much as possible now it is heating up. i really want to tackle this before it gets any more advanced as i love my boy.

ANSWER:   How old is the UVB source?  If it is older than 6 months, change the tube or bulb.  The amount of UVB produced decays with time.  Also, the mesh of the cage if between the light and the animal is also greatly reducing the amount of UVB produced.  I would urge you to invest in a good UVB meter like the Solarmeter to make sure you are providing enough UVB for your chameleon.

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QUESTION: The uvb bulb is a few weeks old, My last one was i for about 4 months. Also there is nothing between the chameleon and the uvb bulb it is mounted along the top of the vivi with a basking branch directly bellow but far enough that the cham cannot touch it. I will order a solarmeter today at the moment i only have a thermometer in there. Do you think i should be providing him with D3, i'm scared to atm as I know excess ammounts can lead to problems too.

Answer
 Consider getting him checked by the veterinarian.  An x-ray and blood panel will tell you if it truly is MBD and how extensive it is.  The vet can give him a treatment and then natural sunlight will help if MBD is present.  I would also recommend adding silkworms to your cham's diet.  Silkworms are higher in natural calcium and have an enzyme that will alleviate pain.