Feather pecking

This morning I noticed a couple of the 3 week old 'incubator' chicks were a little bold on their backs. Running down their spine between their wings they lack the usual chick fluff and only the stubble of new feather growth is showing. I spend far too much time watching them and this was the first time I had noticed it.

I did a mental check of all possible causes;

.... too crowded? no - they don't have as much space as I would like but I am paranoid about space and they do have plenty, although tomorrow I shall increase their area.

.... bored? possibly - they have ad lib food and, of course, water and are fed twice a day on a few greens. Their floor covering is sawdust ( until this week it was Auboise ) which they scratch around in but there is not much else to stimulate them. So I have hung a small wedge of cabbage from their pen door for them to peck at.

..... lacking in protein? no - This tends to be the reason for laying hens to start feather pecking but they are on a balanced chick feed diet, fed ad lib as previously mentioned.

..... sight of blood? no - despite lacking in fluff there is no sign of blood. I shall dust each of the affected chicks just to make sure.

..... too intense lighting? no - after the first week, when they do have the infra red heat lamp, they have a ceramic heat bulb and their only light source is natural daylight.

..... too warm? no - if anything I tend to keep them on the cooler side.

I noticed dust bathing seemed to be the catalyst to feather pecking. When one chick started to bathe in the sawdust the others would rush across and peck the 'bits' from it's back. They don't appear to peck at each other at any other time.
I then came across an interesting article, on the Internet, of research into the relationship of feather pecking to dust bathing and foraging in chicks. It makes fascinating reading and a lot of sense, implying that there is a strong link between the lack of good foraging material and feather pecking. As a result I have added a little straw to their pen, hopefully this along with the other changes I have mentioned, will stop the feather pecking before it gets out of control.