For the 4 Amricanas....
Puffy-Cheeks (Since they grow up, their cheeks will be fluffy).
Prudence (They are very prudent).
Flappy (They can be, er, very flappy. You know, love to fly)?
Grace (Eh, no reason for this one).
For the 4 Buff Orpingtons....
Goldie (The color, of course).
Ginger (Kind of the color, but not really. It's more of like a name that suits them).
Sunflower (Personality and color).
Fluffy (My orpingtons have very fluffy down feathers).
For the 4 Barred rocks...
Moonlight (For the blackish color).
Tiny (Some are very tiny, plus one of ours that died was named Tiny).
Blossom (IDK!!!!).
Sweetie (This is about their personality).
For the 2 Golden Laced Wyandottes....
Gold`e (Pronounced more like "Gold-ay, for the golden laces).
Twinkle (EH, IDK).
For the 3 Welsummers...
Cookie (For the color).
Sweet Pie (Personality).
Moon (Idk, just a good name).
For the 2 Sapphire Gems...
Bluey (The Color. I think)
Midnight (Color).
You can tell your chickens apart by getting chicken leg bands. Just buy them at a local feed store or on the internet. I think they sell special ones for chicks.