Is it considered correct to slaughter the sacrificial animals for Muslims before the Eid prayer, for fear of them being slaughtered by non-Muslims?

Slaughtering the sacrificial animal before its appointed time is not valid, and one does not earn reward for it. If the matter was not stipulated to the Christian manager of the shop, then the owners of the sacrificial animals have been negligent. If the slaughterer was Christian or Jewish, there is no harm in his slaughtering, as his slaughtered animal is permissible to eat. However, if the slaughterer is not from the People of the Book, then his slaughtered animal is unlawful. It is better for you to inform the owners of the sacrificial animals that their slaughter is not valid as sacrifices, and to ask for their forgiveness. Some scholars do not consider it permissible to delegate a person from the People of the Book to slaughter sacrificial animals.