I purchased an incubator on ebay. It is a very cheap one designed for classroom experiments. I placed four chicken eggs in the incubator on February 16, 2008. Are there any signs or clues that I should look for? It does not smell. If the eggs are bad, will it have a foul smell? Since the incubator was cheap and for the classroom, I dont have my hopes up. I am curious. What are the signs of a hatching egg on the 18th day or 19th day? You input will be helpful. I would like to hatch two chicks but that is wishful thinking.