What is the ruling on buying, selling and eating sturgeon?

In some restaurants, for example McDonald’s, where fish is served to customers, it is not known whether the fish is of the type that has scales. In such a case, is there any problem in eating the fish or not?

Recently a documentary showed chicken runs in Pakistan where blood, veins of animals and meat of animals not slaughtered according to sharia are given as food to chicken. It made people worry as to what is the ruling on consuming such chicken? Is it permissible or not?

Is Tatbir permissible? If one has made a vow to perform Tatbir, what is the ruling?

What is the ruling for body hair removal for both the giver and the receiver of the treatment?

What is the ruling for a woman dancing for her husband in the wedding where other women can see her?