how old are your little ones? i'm sure you've read - ideal temp is 95 degrees for the first week, 90 for the second - and so on, reducing temp by 5 degrees each week til they're fully feathered out...
i'd be more concerned about their ability to stay cool when you're hitting 105 - make sure they've got lots of fresh water and shade and ideally cooler than highest temps area. but still use your heat lamp at night if it's getting below their age's ideal temps. more than anything, watch them to see how they're feeling - too hot and they'll be spread out seeking the coolest areas possible and avoiding even each other. too cold and they'll be huddled up looking pretty miserable in the warmest area they can find (and my chicks tend to be WAY more vocal if they're cold...). too too hot and you'll see open-mouth "panting", etc. i try very hard to make sure my chicks have got a wide temperature range to choose from - their heat lamp is at one end of the brooder and i've got it lightly covered at the other end, to offer a much cooler "shaded" area. their food and water is sort of right in between to encourage them to explore and not forget that they've got options!
good luck!