I'm sorry I'm not trying to start an argument but I know my birds. They do need/want the heat. I gave them a night without the heat and they almost froze to death. I came out the next morning and they were huddled together and the temp went down to 48 in the cage. Please do not take this the wrong way but I know my chickens. Tonight it is only going to be in the 60s but the rest of the week it is going to be in the 40s at night with rain. I am putting this in the coop for then just incase they want some extra heat.
Remember that chicks huddle for more than warmth. Like adults, they don't like change - any change. Put something new in their brooder and their first reaction would likely be to get away from it, stand in a tight knot, and stare at it. They huddle for security. If we weren't depriving them of a real mother hen with any of our artificial brooding methods, they'd charge for her and jam themselves under her for protection. And in most cases, by 5 weeks the entire brood of chicks wouldn't fit under her to warm up anymore anyway, so the chicks would get as close to her as possible - huddling. But they still prefer to spend most of their time running around exploring their surroundings, even in temps below freezing. They do the same thing when they learn to roost - get as close to her as possible, a few trying to get under her, but they stick together in a tight little group.
I am sure you know your chicks. Nobody is arguing the point with you. Mine live outside from day one with temps in the teens and twenties, and I haven't lost a single one or had a sick chick yet. There are some situations where Mama Heating Pad isn't appropriate, and trying to train chicks who, in their natural world, wouldn't be needing heat anymore anyway is one of them. So when you put MHP out there, don't be surprised if they don't go under it at all. They may spend a time on top of it and snuggled around it, but they will still huddle, and you'll still go out tomorrow morning convinced that they almost froze to death. I just don't want you to be disappointed when MHP doesn't work as we've described with our younger chicks.
I sure hope you'd still like to give this a try with younger chicks who will naturally want to gravitate to a dark, warm place. We'd love to have you here and see your chicks.
