Does Shariyaah permit buying of animals like goat, cow etc. by weight (and not through bargaining) for sacrifice at Eid-ul-Zoha?
Although animals are not of weigh-able items yet if an identified particular animal is purchased by weighing, it is correct and permissible according to Shari'a and there is no harm in it.
کما فی الھندیہ: و الأعواض المشار الیھا لایحتاج الی معرفۃ مقدارھا فی جواز البیع لأن بالاشارۃ کفایۃ فی التعریف وجھالۃ الوصف فیہ لاتفضی الی المنازعۃ (ج3 ص20)۔
و فی الفتح القدیر:لأنہ لایوزن عادۃ فلیس فیہ أحد المقدرین الشرعیین الوزن أو الکیل الخ (6/167)۔
Ruling on performing Qurbani (i.e. the animal sacrifice) with an animal that appears older than its actual age.
English 2 Rules for the SecrificeRuling on Offering Qurbani in the Event of Lost, Injury or Death of the Sacrificial Animal
English 0 Rules for the Secrifice