Udhiyah – What should be eaten and what should be given away?
Question

What should we do with the udhiyah? Should we divide it into thirds or quarters?.
Praise be to Allah.It is prescribed for the person who offers the sacrifice to eat some of the meat, to give some as gifts and to give some in charity, because Allah says (interpretation of the meaning): 
“Then eat thereof and feed therewith the poor having a hard time” [al-Hajj 22:28] 
 
“eat thereof, and feed the poor who does not ask (men), and the beggar who asks (men). Thus have We made them subject to you that you may be grateful” [al-Hajj 22:36]
It was narrated from Salamah ibn al-Akwa’ (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) said: “Eat some, give some to others and store some.” Narrated by al-Bukhaari. Giving some to others includes both giving gifts to the rich and giving charity to the poor. 
It was narrated from ‘Aa’ishah (may Allah be pleased with her) that the Prophet (peace and blessings of Allah be upon him) said: “Eat some, store some and give some in charity.” Narrated by Muslim. 
The scholars (may Allah have mercy on them) differed concerning the amounts that should be eaten and given as gifts and in charity. The matter is broad in scope but the best way is to eat one-third, give one-third as gifts and give one-third in charity. What one is permitted to eat may also be stored, even for a long time, so long as that will not result in any harm being caused by eating it, except in times of famine, when it is not permitted to store it for more than three days, because of the hadeeth of Salamah ibn al-Akwa’ (may Allah be pleased with him) who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: “Whoever among you offers a sacrifice should not have anything of it left in his house after three days.” The following year, they said, “O Messenger of Allah, should we do what we did last year?” He (peace and blessings of Allah be upon him) said, “Eat some, give some to others and store some, for last year the people were having a hard time and I wanted you to help (the needy).” Agreed upon. 
With regard to the permission to eat and give away the meat of the udhiyah it makes no difference whether the sacrifice is voluntary or obligatory, or whether it is offered on behalf of a living person or a deceased one, or in fulfillment of a will, because the executor of the will takes the place of the person who made it, and the person who made the will would eat, give away and give in charity. And because this is the custom among people, and that which is done customarily is like that which is spoken.  
In the case of one who has been delegated to offer the sacrifice, if the person who appointed him has given him permission to eat of it and give some as gifts and in charity, or if that is indicated by analogy or by custom, then he may do that, otherwise he should give it to the person who appointed him, who is then in charge of the distribution of the meat.
 It is haraam to sell any part of the udhiyah, whether that is the meat or any other part, including the skin. And the butcher should not be given any part of it in return for his work or part of it, because that is like selling. 
But if a person gives the butcher some of it as a gift or as an act of charity, then he may dispose of it however he wishes, by selling it or otherwise, but he should not sell it to the one who gave it to him.