One cause of weak yolks is lack of protein. I'd try feeding an all flock (higher protein) and supplement with oyster shell on the side. Or, if you have lots of lower protein food left so don't want to switch just yet, try feeding them a bit of scrambled eggs, a few sunflower seeds or mealworms, but I go real easy on those last two as they're fattening.
Thank you! I did grab a "treat" of black seed/meal worm mix and will grab an all flock next timeI am at the feed store! (these girls are definitely not over weight- I actually got the mix to add a some weight! So I should be ok til the next trip to the store! I don't give treats often. )
