As you can see, there are many ways people raise chicks. You are the one who is with them, so you will have a better idea about how they are doing. Their behavior is the best way to tell when they are comfortable. If they pile up tight under the lamp, they're cold. If they try to escape the lamp, they are hot.
At over 2 weeks old, 30*C is warm enough, so you could use a weaker bulb if you have one, or put it up higher. Make sure it is stable. Low night temperatures will be a problem for them until they are a little older.
Are they able to get in and out of your brooder box?
How are they doing now? [Hint: we'd love more pictures

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