Brooding is usually done between the first four (4) weeks of the chick’s life. At the first week, you have to maintain them at a temperature of 32C-34C, 30C-32C at the 2nd week and 28C-30C at the 3rd week.
After four (4) weeks, their feathers are enough as a source of heat. Brooding them beyond 4weeks is undesirable and could be stressful for the birds.
See also: The Best age to Purchase Point of Lay Birds