Assalamu Alaykum: My husband works at a pizza and fried chicken restaurant. The fried chicken he sells is halal, but some pizza ingredients are made from not halal chicken and not halal beef, I mean just regular chicken bought at a regular supermarket, not at the halal store. He wants to know if is it allowed in Islam to sell no halal food and if his earnings in this case are halal or not. He does NOT sell any kind of alcohol beverages or pork.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

If the people of the country where you reside now are from the people of the Book and they are not predominantly atheist, then in principle the meat of animals slaughtered by them is lawful. Allaah Says (what means): {This day [all] good foods have been made lawful, and the food of those who were given the Scripture is lawful for you.}[Quran 5:5]; this is of course as long as the conditions of lawful slaughtering are observed, but if it is known that the animals are strangulated or electrocuted to death, then the meat becomes forbidden.  For more benefit, please refer to Fataawa 82323 and 84072.

Therefore, it is permissible for your husband to sell the pizza the meat of which is mixed with the meat of animals slaughtered in a country whose slaughtered animals are ruled to be permissible, and his earning from such work is lawful unless it is proven to him that the animals are slaughtered in an Islamically illegal way; in which case it is not permissible for him to sell it.