Re: How can we keep moth eggs viable, so they can hatch?

I can't identify the moth from your description but I bet your county extension agent can; just give that office a call. They should be able to identify the moth and tell you its primary host plant. The site below has a great section on caterpillar rearing but you'll still need to know the host plant in order to successfully rear the larvae.

http://www.naturalpartners.org/InsectZoo/Curriculum/ArthropodCareDirectory/#Caterpillars