How old is she? Pullets will lay smaller eggs for some months. However, my 2 Faverolles (2012 from Ideal) had always underperformed. In fact they have both averaged 46g over their laying life, well under USDA Medium (> 50g) and never larger than the low end of USDA Large (> 57g) and those were rare. Never got a double yolk from either of them though I have from the BAs when they have laid eggs that are WAY off the USDA charts. My EEs (your "Americana") lay from the higher end of Medium and the low end of Large (> 57g) to Jumbo (> 71g)