How long does it take to acclimate? Mine are three weeks old.. they have been inside and it’s pretty warm in there.. I put them out to play on warmer days and they seem to get chilled fairly quickly.. I was gonna put them out tomorrow but put the heat light where they can warm up if needed.. also, have been turning the light off at times during the day..
If they act like they're cold outside then they may need more time inside or at least with some supplemental heat. Gradually reduce how much heat they're getting each day (either by raising lamp or turning it off for longer periods of time) and continue putting them out when you can, weather permitting. Assuming temperatures don't fluctuate too much you can probably wean them off heat completely after a week or so.
If you need them out ASAP but still want to supplement heat, then make sure the heat lamp is at least VERY well secured and start reducing the length of time it's on from there.