Dubbed means the comb and wattles [and sometimes the ear lobes] are surgically removed. It is mostly done to roosters because they have bigger combs. it is to prevent frostbite and injury to the comb of large combed birds and [historically] in fighting breeds to give the opponent nothing to hold on to, and is also part of the breed standard for many breeds of now solely ornamental gamefowl, though usually only for mature males.
it looks like the black offspring does not have much of a comb either, though, so maybe she never had all that much. Unless that one is very young and has yet to grow something.
