Yes it is permissible to sacrifice a larger animal for 'aqiqah, but sharing it is rather not. For details read the following:
Ahadith on 'Aqiqah
Here some evidences for performing 'aqiqhah:
- 'If anyone has a child born to him, and wants to sacrifice for his child, then let him do it.' (Muwatta' Malik and sunan abi Dawod)
- "Every boy is pawned against his 'Aqiqah, to be slaughtered on his behalf on the seventh day of his birth, his head is to be shaved, and he must be given a name."
Related by the five Imams (Ahmad and the four Imams). At-Tirmidhi graded it as Sahih. (Bulugh al-Maram)
- They entered upon Hafsah bint 'Abdur-Rahman to ask her about the 'Aqiqah. She informed them that 'Aishah had informed her, that the Messenger of Allah (ﷺ) ordered them that for a boy, two sheep were sufficient, and for a girl one sheep. (Jami' at-Trimdhi)
From this we may conclude that a sacrifice for the new born is sunnah it is even sunnah to sacrifice -if possible- two sheep for a boy and one for a girl.
Ahadith on sharing a sacrifice
- In the year of Hudaibiya (6 H ), we, along with Allah's Messenger (way peace be upon him), sacrificed a camel for seven persons and a cow for seven persons.
(Sahih Muslim, Muwatta' Malik, sunan abi Dawod and Jami' at-Tirmidhi 1 & 2)
Imam at-Tirdmidhi commented on the fiqh of this hadith saying:
وَالْعَمَلُ عَلَى هَذَا عِنْدَ أَهْلِ الْعِلْمِ مِنْ أَصْحَابِ النَّبِيِّ صلى الله عليه وسلم وَغَيْرِهِمْ يَرَوْنَ الْجَزُورَ عَنْ سَبْعَةٍ وَالْبَقَرَةَ عَنْ سَبْعَةٍ . وَهُوَ قَوْلُ سُفْيَانَ الثَّوْرِيِّ وَالشَّافِعِيِّ وَأَحْمَدَ . وَرُوِيَ عَنِ ابْنِ عَبَّاسٍ عَنِ النَّبِيِّ صلى الله عليه وسلم أَنَّ الْبَقَرَةَ عَنْ سَبْعَةٍ وَالْجَزُورَ عَنْ عَشَرَةٍ . وَهُوَ قَوْلُ إِسْحَاقَ وَاحْتَجَّ بِهَذَا الْحَدِيثِ . وَحَدِيثُ ابْنِ عَبَّاسٍ إِنَّمَا نَعْرِفُهُ مِنْ وَجْهٍ وَاحِدٍ .
My own translation take it carefully:
And this is how the people of knowledge among the sahib and others have done they considered seven shares fro the sluaughtered camel and seven for the cow. And this is the opinion of Sufyan a-Thawry, a_Shafai'i and AHamad. While ibn 'Abbas has narrated from the prophet Allahs prayers and belessings be upon him that a cow is shared for seven and a slaughtered camel for ten. And this is the opinion of Ishaaq and he held it as an evidence. But we only know the hadith of ibn 'Abbas from one chain.
In his commentary on the other hadith he added: Ibn al-Mubarak and one of two opinions of Ishaaq to those who say the shares are of 7 for camel and cow.
In his commentary on sahih Muslim imam an-Nawawi discussed the fiqh of this hadith saying that there is a dispute about the permission for sharing a sacrifice of Hady (in Hajj) a Shafi'i held the opinion that it is permissible no matter if it is a hady which is wajib (ordered on him) or nafl (optional), no matter if the people sharing it are doing it for the sake of Allah or just to eat flesh, Ahmad and a majority of scholars followed this opinion. Some malikis and Dawod said it is permissible for an optional hady. Malik held the opinion that this sis not permissible (note that he has compiled the hadith). Abu Hanifa held the opinion that this is permissible if they wanted to sacrifice it for the sake of Allah. And all are in consensus that sharing a sheep is not permissible.
And there's also the hadith saying:
The Prophet (ﷺ) said: A cow serves for seven, and a camel serves for seven. (Sunan abi Dawod)
Who is asked to perform 'aqiqah?
According to this fatwa in islamweb #2287 the person who is in charge for the new born is the one who is asked to do this sacrifice. The shafi'is said nobody else is allowed to do it unless this person gives permission for that. The malikis said the person who is asked to perform it is the father. The hanbalis said nobody else is allowed to perform it except the father as long as he is alive or there's any kind of impossibility/refusal and if somebody else performed it, it would be considered as makrooh but valid.
Is it ok to sacrifice a larger animal for 'aqiqah?
It is clearly permissible to sacrifice a cow or a camel if possible and I don't know of any school refusing this. Some scholars based the ruling on analogy on hady and odhiyyah.
Can the sacrifice for the 'aqiqah be shared at all?
From what I've quoted above it sounds rather makrooh to share a sacrifice for 'aqiqah.
The malikis and hanbalis hold the opinion that sharing this sacrifice is not permissible. The fatwa on islamqa #82607 holds this position as the strongest.
Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him) said: It is not acceptable to share an ‘aqeeqah, so it is not acceptable to offer a camel on behalf of two or a cow on behalf of two, so it is less likely to be acceptable on behalf of three or four. The reason for that is:
Firstly that there is no report of sharing an ‘aqeeqah, and acts of worship are based on following the texts.
Secondly it is a ransom, and a ransom cannot be divided. It is a ransom on behalf of a soul, and if the ransom is on behalf of a soul, it must also be a soul.
No doubt the first reason is stronger, because if there was a report to indicate that an ‘aqeeqah could be shared, then the second reason would become invalid, so the basis of the ruling is that there is no report to indicate that. (source: islamqa #82607)
The shafi'is allowed it based on qiyas on hady and odhiyyah.
This fatwa on islamweb #13795 says the majority say sharing the sacrifice of 'aqiqah is not permissible as there's no evidence saying that anybody at the time of the prophet () or later has done so.