In Hidaayah and other Fiqh books it is clearly stated that the meat of the Ahl-e-Kitaab is halaal.

Answer

What is written in Hidaayah and other kitaabs regarding the meat of the Ahl-e-Kitaab is not applicable to the situation in this age. In this age even Muslims deal in and consume carrion. Experience has established that the animals and chickens are killed in haraam ways. Furthermore, the total supervision which is required is no where to be found. Supervision is a myth. The reality is only money for the coffers of the halaal-certifiers. They are operating a racket in the name of the Deen for the sake of money.

The situation on the ground determines the fatwa. If it is known that the Ahl-e-Kitaab is selling pork as beef, will it be permissible to consume it without investigating? When it has been established beyond doubt that the chickens for example are not slaughtered, but are killed incorrectly, then it will be stupidity manifest to aver that such improperly cut animals are halaal simply because the slaughterer happens to be a Muslim or a Kitaabi. If a Muslim does not recite Tasmiyah intentionally, the chicken is haraam. Now this is what is happening in all the chicken-killing facilities.

If a Muslim does not sever the requisite number of neck vessels, the chickens are haraam. This is precisely what happens, and what our investigations and experience have confirmed. And, this is besides the other factors of hurmat which we have explained in numerous articles and booklets. Christians no longer effect Thabah. They kill animals brutally. When it is an irrefutable fact that machines are killing the chickens, etc. which are imported, then by what stretch of Shar'i reasoning can it be claimed that such carrion is the halaal meat of the Ahl-e-Kitaab? The Orion people are Christians or Jews. The scandal of pertaining to these members of the Ahl-e-Kitaab in cahoots with the MJC gang is still fresh in the mind.