Reciting Talbiyah in unison

Is it Sunnah for the pilgrims to recite the Talbiyah in unison, or should each person recite it on his own?.

Praise be to Allah, and blessings and peace be upon the Messenger of Allah:

Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him) said:

It is not narrated that the Sahaabah (may Allaah be pleased with them) recited the Talbiyah in unison. Rather Anas ibn Maalik said: We were with the Prophet (peace and blessings of Allaah be upon him) – meaning during the Farewell Pilgrimage – and among us were some who recited “Allaahu akbar”, some who recited “Laa ilaaha ill-Allaah”, and some who recited the Talbiyah. This is what is prescribed for the Muslims: for each person to recite the Talbiyah by himself, and not to pay attention to what others are reciting.

And Allaah knows best.