To reduce stress and mortality, the brooding temperature should be monitored closely in order to ensure that it is just right. The best indicator that the conditions inside the brooding ring are optimal is generally the chick behavior to heat. This will give you a very clear idea on whether you have provided the best conditions.
If the chicks in the brooding area are spread out evenly and are comfortable, this is generally a sign that the conditions in the brooding area are just right and you will not need to make additional adjustments on the temperature and humidity. The below pictures illustrate the effects of various temperatures on the chick behavior:-