They are 4 weeks old and for the last few days, we haven't been using any heat lamp. Tonight is a bit colder but at night, they always huddle even when it's 85 or 90 degrees out so how can I tell if they're too cold at night? I had a thermometer in there but they knocked it down and it's buried somewhere beneath the bedding so I don't really want to go digging for it tonight. I think the low is supposed to be around 65 tonight.