It is halachically permissible both to donate breast milk, and to receive human donor milk for your baby if needed.
In the halachic literature, there is some preference to use a wet-nurse who is Jewish, or at least refrains from eating non-kosher food. Today, however, the safest source of human donor milk is an officially recognized milk bank, which screens donors and pasteurizes the milk. It is fully permissible to use human donor milk from a milk bank. The baby’s health overrides any concerns about the donors’ religious identities or practices.
Please feel free to get back to us with any further questions.