Bismillahir Rahmanir Raheem
Wa'alaykum 'Assalam wa Rahmatullahi wa BarakatuhuPraise be to Allah who is the Lord of the Worlds, and may Endless Blessings be showered upon His Most Beloved, and Final Messenger of Islam, Hadrat Muhammad Mustufa Salla Allahu ta'ala 'alayhi wa aalihi wa SallamJazak'allah for your valued question. The age at which Hadrat Halimah Sa'dia
(Radi Allahu anha), brought back the Beloved Messenger of Allah
(Salla Allahu ta'ala 'alayhi wa Sallam) was first at the age of two. It was quiet normal, for the women of Banu Sa'd, to come to Makkah, in order to find new borns, whom they could feed, and in return be granted rewards for doing so. This system had existed partly due to poverty, and partly so that the parents of the children could keep the children away, so that they may learn the eloquent Arabic, and keep away from the mischief of the city.
However, when Hadrat Halimah Sa'dia
(Radi Allahu anha), noticed the blessings that the Messenger of Allah
(Salla Allahu ta'ala 'alayhi wa Sallam) had brought into their house, and there were very many, she did not want to give up The Beloved Messenger of Allah
(Salla Allahu ta'ala 'alayhi wa Sallam), to His parents so early, therefore according to the famous books of
seerah, at the end of the two year period, she went back to Makkah to see Hadrat Aminah
(Radi Allahu anha), the mother of the Beloved Messenger of Allah
(Salla Allahu ta'ala 'alayhi wa Sallam).
She stated that the air and water of the area she was from, was better for the Messenger of Allah
(Salla Allahu ta'ala 'alayhi wa Sallam), and that, the atmosphere of the city, and its bustle was not appropriate for Him,
(Salla Allahu ta'ala 'alayhi wa Sallam).
When Hadrat Halimah Sa'dia
(Radi Allahu anha) insisted, she was granted permission, and the beloved Messenger of Allah
(Salla Allahu ta'ala 'alayhi wa Sallam) remained with her for another two or three months, afterwhich, the event of the opening of the chest (
shaqq-e-sadar) took place, at which stage, the beloved Messenger of Allah
(Salla Allahu ta'ala 'alayhi wa Sallam) was brought back to His mother.
In summary, the Messenger of Allah
(Salla Allahu ta'ala 'alayhi wa Sallam)completed His period of suckling (radha'ah), and stayed with Hadrat Halimah Sa'diah
(Radi Allahu anha), for another two or three months, when the
shaqq-e-sadr event took place.
I hope that this is a sufficient answer to your query. If you have any further questions relating to this topic, please do not hesitate to ask.
Wallahu A'lamu BiththawaabM. Waseem Ashrafi