When I feed my crickets I always feed them something fresh, and some special cricket pellets that have a high vitamin/mineral/calcium content. These pellets are all sorts of bright colours; blue, pink, yellow etc. I noticed something rather odd the other day, in that my crickets were changing colour!! A number of them had recently shed, so were a bit transparent, and you could see which colour pellet they had eaten very clearly!!! So at the moment I have pink and green crickets running around!!!