Question Summary:
Reversible and irreversible stunning

Question Detail:

I would like to know if the animals that are stunned (reversible or irreversible) thereafter slaughtered halal way. Are the animals halal consume? 

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
The issue of stunning animals before slaughtering has been extensively researched. It is widely believed that stunning is regarded as cruelty to animals.  You may refer to the following links for further read on this[1].
Nevertheless if an animal is stunned and is alive before slaughtering , the animal will be halal.
 
Abu Ali ad-Dagestani
Student Darul Iftaa
Moscow, Russia
Checked and Approved by,
Mufti Ebrahim Desai