Quote: Could it be that because it is colder that they are using energy to keep warm, instead of in a brooder with a heat lamp?
You could be on to it here. Right now, I have all my chicks outdoors in pens or running free with hens so I have no indoor chicks to compare them to. In the past when I have been growing them out indoors as well as outside, I have noticed the phenomenon you describe. It has been atrociously hot and humid here so even my chicks weaned at 5 weeks old running around EVERYWHERE seem to be growing pretty good. One thing I have noticed is that if you do not confine the hen with their high protein feed, they eat very little of it. They will eat bugs, grass, raid the other feeders and only eat a little bit of THEIR feed. They prefer to forage for their food. I find the chicks outdoors are very hardy and vigorous though as you describe & they usually eventually catch up with the others. More to observe and learn though. Please do report what you notice. Thanks for the pictures.
You could be on to it here. Right now, I have all my chicks outdoors in pens or running free with hens so I have no indoor chicks to compare them to. In the past when I have been growing them out indoors as well as outside, I have noticed the phenomenon you describe. It has been atrociously hot and humid here so even my chicks weaned at 5 weeks old running around EVERYWHERE seem to be growing pretty good. One thing I have noticed is that if you do not confine the hen with their high protein feed, they eat very little of it. They will eat bugs, grass, raid the other feeders and only eat a little bit of THEIR feed. They prefer to forage for their food. I find the chicks outdoors are very hardy and vigorous though as you describe & they usually eventually catch up with the others. More to observe and learn though. Please do report what you notice. Thanks for the pictures.