I don't understand what the 新たに is doing here...? I've read example sentences with 雇う and 雇い入れる and I can't perceive the difference...?
雇い入れる means to newly take someone into employment. 雇う can mean the same thing, but it also means to have/keep someone as an employee.
- 彼を10年間雇い続けた。: OK
- 彼を10年間雇い入れ続けた。: NG
- 彼女を雇い入れるのをやめた。: (i.e., she could not enter this company)
- 彼女を雇うのをやめた。: (also means she was fired)
According the dictionary あらた【新た】 means "again", "once more":
So 新たに雇う means "to hire again", "to hire more people".
雇う simply means "to hire".