changing color?

i bought 3 bearded dragons babies ( they are 3 month old and are the "regular" type).
fist 2 were dark and one looked a little on the orange side, the next day they were all dark, then the one that was "orange looks dark and another changes to an orange color....
i know they have different colors/types of dragons and that they will start showing more color as they get older...but i thought the regular stays the same.
or does the heatlamps have anything to do with it?
since it is really hot right now in cali i do not have the heatlamp on, but i do have a repta-sun sun-glo during the day for uv rays on and at night i turn the blue/black repta-sun on.
but i notice the change usually when i take them out and hold them in the regular light.
they also like to hang around in their water dish/pool.
any ideas about a reason for the color changing?
thanks
dianne

Natural sunlight will definetely FIRE them up. I keep mine outside and notice that they change colors in relation to the temp and Direct sunlight. During mid day when temps are the hottest they tend to be bright. Towards the end of the day in the evening when the sun goes down they get much Darker. Reptiles in general are usually darker when they need to heat themselves up. Darker colors absorb more sunlight and allow them to heat up faster and use the most of whats available to them.