Turkey eggs take about 4 weeks to hatch.If she will go broody the you should be able to use her to hatch chicken eggs.If you want to know if they are fertile then try and candle them when she is gone.
Something similar happened to my goose.It took me days to figure out what was wrong.Finally I found a small scratch on his le.I did not think that would cause it then someone told me that waterfowl have fragile
legs.so i medicated the scratch with neosporin and some dermoplast spray.pretty soon...