We bought 7 CX to go with our layer order that are now in a moveable pen outside. All of them are 4.5 weeks old and almost fully feathered. It is plenty warm outside as the sun is shining and they are blocked from the breeze. I went out to check on them at lunch time today and 1 was dead, 5 others were bloody and couple had entrails hanging out from above the vent but below the tail. They all seemed fine yesterday and didn't notice anything early this morning. I went ahead and culled all that showed any signs of problems because they are in the same pen as my layers (who all look great). What could have caused this? I didn't take pictures because I was just trying to get it all cleaned up as fast as possible. do I need to be worries about the other birds in the pen that shared water/feed/space with them? I have moved them all to a different location so they have fresh ground.