I’ve learned today (since picking the girls up around 8am) that the opening/closing of doors and/or drafts of cool air have had an effect on their brooder temperature. I’ve just been adjusting it by moving the lamp closer/further heighten it and it would even itself out. So that’s something I can attest to; the temps can fluctuate based on drafts or surrounding temps. Our weather dropped 20 degrees today compared to yesterday and so me letting the dogs in and out, or my in/our for other reasons have an affect on the brooder since it’s in the living room. It’d drop to about 87 or peak at about 93. So when I noticed this fluctuation, I promptly moved the bulb to accommodate. Doesn’t take much of a height adjustment to level it out.
I’d suppose keep an eye on contributing temp factors like that too.