I have 15 Columbian Wyandottes that will be 6 weeks tomorrow and 2 of them are similar to yours. They have grown a lot more feathers since I put them on meat based starter (started with Purina) but they are still way behind. I know one was very small when it came & was behind, but the other was not. The roo theory is what everone comes up with, however the roo I ordered feathered in fast just like the other 12, so only time will tell. I can't wait to see how many actually are roosters and if the one marked as a roo, really is one. He has lost the food coloring I painted him with after I took off the band, but he is one of only 3 with a straight comb, so I am pretty sure which one he is. I got mine from Meyer, so chances are they came from the same place as yours. Guess we have to wait and see.