I found a goose egg in my garden?

Hi I live on a river and this morning my family and I found a goose egg in our garden!!! My mother just put fertilizer in the garden yesterday so we know it was either earlier today or last night. It was cold so we ran it gently under lukewarm water, made a "nest" in a basket, put the egg in and placed it under a lamp. The egg was right by our porch so we know we didn't take it from the mother goose. Please help us!!! We really want to help it live! I will try everything you suggest (as long as it's safe!) Thank you so so much! :(