I'm pretty sure someone else has noticed this, but I just had to share because I thought it was so cool... In the past, I had a black hen hatch a few chicks, some which came out black, some white, and a few with the chipmunk markings. I had another set of chicks hatch about the same time in the incubator and wanted to give them to her to raise, since she only had about 5 she hatched herself. She had no problem with taking in the black chick, but the other chicks were Blue laced red, so have a different coloring and marking altogether. She pecked these chicks and basically said "no" to those. I figured it was because she thought the other chick belonged to her to start with, so I just let her keep it. The other day I had an OEGB hatch out a few babies. Some were chipmunked, two were blue. I discovered that my little mutt barred hen had also hatched out a chick, a little black one. Because I had to separate the OEGB and her babies from the rest of the flock, and I worried that the one black chick wouldn't make it loose in the yard, I decided to put the black chick in with the game hen. She wasn't going to have any of that! She started pecking it right away, so I had to take it out and gave it back to it's mama. (It's doing okay so far...) Today, I went back into the OEGB pen, and my other hen had just one chick running around in there with her, so I took it away and gave it to the first hen with the babies. This one was also chipmunked. The mama didn't even blink and it's in there like it's always belonged. I have three more OEGB eggs hatching now and expect them to be the same color, so I'll probably stick them in with her as well. It was an unplanned experiment, but apparently hens imprint on the color of their chicks. I was always under the impression that hens respond only to the peeping of their chicks, but now I think that peeping has nothing to do with it. I know chickens can recognize who belongs in their flock and who doesn't, so I guess this would make sense.