There is nothing wrong with slaughtering the hadiy in Muzdalifah
Question

                Is it permissible to slaughter the hadiy in Muzdalifah?.
Praise be to Allah.Slaughtering the sacrifice in Muzdalifah or in Makkah or in Mina is all permissible; it is permissible to slaughter the sacrificial animal (hadiy) anywhere that is within the boundaries of the Haram, and there is nothing wrong with it, because the Prophet (blessings and peace of Allah be upon him) said: “All the ravines of Makkah are roads and a place of sacrifice.” End quote.