Answer
Wa `alaykum as-salamuwarahmatullahiwabarakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
At the very least, a third of the udhiyyah should be eaten, a third should be given as gifts, and a third should be given in charity.
Responding to the question, Sheikh M. S. Al-Munajjid, a prominent Saudi Muslim lecturer and author, states,
The command to give the meat of the sacrifice of udhiyah in charity is reported in a number of hadiths and so is the permission to eat some and preserve some.
Al-Bukhari and Muslim reported that Aishah (may Allah be pleased with her) said: Some poor families among the people of the desert came to Madinah on the occasion of Eid Al-Adha during the lifetime of the Prophet (peace and blessings be upon him). The Prophet then said, “Store with you meat sufficient for three days, and whatever is left give in charity.” Thereafter, they (the Companions) said, “O Messenger of Allah, people used to make water-skins from [the skins of] their sacrificial animals and tomelt down fat from them.” The Prophet said, “What about that?” They said, “You forbade us to eat the meat of our sacrificial animals after three days.” He said, “I forbade you to do that because of the poor Bedouin people who came [to Medina last year], but now eat some, preserve some, and give some in charity.”
Imam Nawawi commented: The phrase ‘I forbade you to do that because of the poor people who came, but now eat some, preserve some and give some in charity’ clearly indicates that the prohibition of storing the sacrifice meat for over three days no longer applies. It also includes a commandment to eat some and to give some in charity.
With regard to the portion to be given in charity, if it is a voluntary sacrifice, then giving some of it in charity is obligatory, according to the view regarded as correct by our [Shafi`ite] companions.
It is even preferable (mustahabb) to give most of its meat in charity. They [our Shafi`ite companions] said: At the very least, a third should be eaten, a third should be given as gifts, and a third should be given in charity. There is another opinion that suggests a half to be eaten and a half to be given in charity. This difference of opinion is about the best minimum amount preferable. As for fulfilling what is required, one may give in charity any amount that is considered as charity. Still there is another point of view that one does not have to give any amount in charity.
As for eating from it, it is only mustahabb, not wajib (obligatory). The majority of scholars interpreted the command to eat of it in the Quranic verse that reads, {That they may witness things that are of benefit to them, and mention the name of Allah on appointed days over the beast of cattle that He has bestowed upon them. Then eat thereof and feed therewith the poor unfortunate} (Al-Hajj 22: 28) to imply recommendation or permission; particularly it followed a previous prohibition.
Imam Malik said: There is no specific limit to what may be eaten or given in charity or used to feed the poor or the rich- whether one gives it uncooked or cooked.
The Shafi`ite scholars said that it is mustahabb to give most of it in charity and said that at least one-third of it may be eaten, and one-third given in charity, and one-third given away as gifts.
They said also it is permissible to eat half of it; but it is more correct to give some of it away in charity.
Imam Ahmad said: We adopt that narrationof Abdullah ibn Abbas (may Allah be pleased with him), ‘One should eat one-third, feed one-third to whomever he wants, and give one-third in charity.’ This is also the opinion of Ibn Masud and Ibn Umar. No conflicting opinion is known among the Companions.
The reason why there is a difference of opinion as to how much of the sacrifice may be given in charity is that there are conflicting reports.Some reports were narrated without specifying a particular amount, such as the report of Buraydah (may Allah be pleased with him) who said: The Messenger of Allah (peace and blessings be upon him) said, “I had forbidden you to eat from the sacrificial meat for more than three days so that those who could afford it could give to those who are poor.But now you may eat as you wish, feed others from it, and store some.” (At-Tirmidhi). Scholars from among the Companions of the Prophet as well as others followed this norm.
Allah Almighty knows best.
Source: www.islamqa.info.