My wife and I are new to raising chickens, so if this is easily answerable then it is borne entirely of inexperience.
We have 2 Ameraucanas living in a mixed flock with 8 other birds (2 buff orpringtons, 2 white leghorn, 4 rhode island red). The flock ranges in age from 12-15 weeks, approximately. We have noticed that the two Ameraucanas are frequently missing big patches of feathers on their backs. My wife suspects it is because they are being picked on / pecked by the others. I think she might be right because they are the most skittish of our birds and will spend time in the coop while the others are out in the run.
We have tried to rule out mites or other pests by inspecting the birds. We also have not noticed this happening to any of the others since they moved out of their big cardboard box in the garage and into their coop - about 5 weeks ago.
Any suggestions or ideas would be much appreciated!