Which chickens are my eggs from?

[Scybrix]

I have a young flock, hatch date around 8/14/13, of 2 RIW and 2 Dominique's. They started laying just after Christmas but I have no idea which eggs belong to which chickens. I think up until today have only been laying, we usually get 2 eggs a day, today we had 3 and the 3rd egg is a different shape and size. Any ideas? I am surprised they are laying already, seems a little young and it's been cold.
The pic with 3 is from today, as you can see one is smaller and more oblong in shape, the single egg was the first ever. Thoughts as to who started laying first?

 

[fried green eggs]

Congrats on getting first eggs. Hens combs pink up and look larger when they start laying. Smaller paler combs may be newer layers. Hope that helps.

 

[Scybrix]

They're all pretty big and very red, but of. Of course I have an untrained eye! We are getting 2-4 a day now, usually 3. Thanks!!!