my cham had the same colors when i use to house my first two chameleons together and she got pregnant. soon ofter that i read there not suppost to be housed together just to sex them and then seporate, when my cham was with the male in the same cage she was always that color, black n yellow really dark colors, the day that i bought another cage and seperated them she turned to a light green and yellow very beautiful, so im asuming she was verry happy to be in a seperate cage, and the dark colors would mean she was not comftable/happy being in the same cage with the male. or maybe shes was about to lay her eggs? could be either one but im no export just assuming thats why she had those dark colors like your friends cham.