Humidity..??? Incubating chicken eggs..

[TenneesseeChick]

I don't have the money to purchase a humidity level indicator in my incubator it's just a 8 inch high Styrofoam lined wooden hinged box with a light bulb and bath room exhaust fan blower and a quart plastic container of water and 50 fertile eggs in cardboard egg cartons. I turn each carton several times a day..the temp remains at 98 to 101 all the time...what are my chances with this home made incubator..I even have a plexiglass viewing window and two thermometers..should I put a sponge in the container of water???

 

[Rod-T]

You need humidity guage . . Simple cheap one at least