The black could be scabs from them hitting the comb on something or getting pecked on the comb. I must admit, I have accidentally made a comb or two bleed a little bit while trying to catch a bird that decided to run along the wire of the cage and they hit their comb on the wire. A lot of times it doesn't take much for the comb to bleed. But I would suggest looking up fowl pox so you can tell the difference in peck scabs and fowl pox scabs. One thing you can do to see how well the birds have been taken care of is to ask when the birds were last treated for mites/lice and wormed.Yes I look at all those things.. I don't know the cause of the black you see on a lot of combs but I don't like it..and I do look at the overall appearance of the bird... I understand a broken feather or molting but if it looks unkept to my standards I don't want it because I'm afraid it hasn't been properly cared for. I also don't like seeing some people mishandle birds. Im not referring to just pucking up by feet as its necessary at times. I'm talking about ones who literally stuff them in boxes together where they can't move or fling the cages around like it doesn't bother them to be slammed around. I've seen this at swaps. I despise it.lol.
Which reminds me, it's time for my birds spring worming
