Each and every one of those eggs is different! You should be able to figure it out no problem :)
Next time you eat eggs, make note of which one has the bullseye and try to determine if the same egg the following day has it as well.
You should be able to tell the eggs apart. Especially with so few chickens. They all lay an egg that is very individual. The shades usually don't change much (not considering after a molt, or other factors), and they are almost always the same shape.
If they all look similar to you, you can...
Click to enlarge. Difference between feathers in males and females.
Your black one is laying, or close to.
Note: The comb type on these birds is pea. It does not apply to your situation. Hard to compare by comb unless you have both cockerels and pullets.