Beautiful bird, but you should treat her feet and legs for scaly leg mites and all of your other chickens too as this might have spread already during the 4 weeks since she joined.
What do you feed her, is she in good condition or maybe too fat? Did you inspect for lice or mites?
My two Silver Laced Wyandottes hatched in April 2015 and are each still laying 4-5 eggs per week.
They go broody twice a year and after about 8 weeks of caring for their chicks they start laying again.