Growing...or not?

Those charcoal agar plates seem to be growing when I looked at them this morning, but somehow not all of them are growing. I cultured 4 strains of Campylobacter on both agar plates with/without supplement, and the result shows that the one with supplement seems to be more or less easier to survive. As the agar plates with supplement were made 1 year ago (which is quite old), I made another batch of charcoal agar plates with supplement, then subcultured those surviving colonies and also culture another 4 new Campylobacter beads on the new plates. Hopefully they'll grow better than last week...or will they?