Treatment for pigeon chest depends on patients age and severity of chest deformation.
Young people before the body growth has finished (skeletally immature child) and with a mild deformity, are the best candidates for treatment with dynamic chest compressors and body casting.
If the deformity is moderate or severe, and there is an adverse effect on lungs function, surgery correction is the treatment of choice.
Surgical results are better when the surgery is performed before adolescence.
After adolescence, some male find bodybuilding helpful in hiding the deformity.

Consult a thoracic surgeon!