It is essential that the sacrificial animal be slaughtered by a Muslim with the intention of offering a sacrifice (udhiyah)
Question

 
In this part of the country (Vanc. ,Canada) and maybe other ares also, the farmers deal with us in the following manner. When you go to buy an animal, they quote you a per pound rate. This means that after slaughtering the animal, they weigh it and charge you a certain amount per pound. This includes the cost of the animal and the fees for using his premises (for slaughter) and the cutting and wrapping fee. For the udhiyah is this permissible?
 Or is it that the animal must first be purchased and then afterwards only the fees can be paid. The farmers are not willing to do this as they are afraid they may lose on the deal if they do it. I do believe that if people try hard enough they may find those who maight agree. However, I am not certain. Nonetheless, the question is, can the udhiyah be considered correct if the method of purchase mentioned above is followed?.
Praise be to Allah.It is a necessary condition of the sacrifice that the animal be slaughtered by a Muslim with the intention of offering a sacrifice (udhiyah); it is not sufficient to slaughter it for the meat. 
Al-Nawawi (may Allah have mercy on him) said in al-Majmoo’ (8/380): The intention is a condition of the sacrifice being valid. 
There is nothing wrong with buying the animal in the manner described in the question, so long as the worker slaughters it with the intention of offering a sacrifice. That is if the worker is a Muslim; otherwise one of you should slaughter it, then the worker can cut it up. 
Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said in al-Sharh al-Mumti’ (7/494): 
It is not correct to delegate the slaughter of the udhiyah (sacrifice) to a kitaabi (i.e., a Jew or a Christian), even though meat slaughtered by the People of the Book is halaal. Because slaughtering the sacrifice is an act of worship, it is not correct to delegate it to a kitaabi, as a kitaabi cannot be involved in acts of worship that draw the Muslim closer to Allah, because he is a kaafir (disbeliever) whose worship is not accepted. If his acts of worship are not valid when done on his own behalf, they cannot be valid when done on behalf of another. But if a kitaabi is delegated to slaughter regular meat for eating, there is nothing wrong with that. 
And Allah knows best.