Its winter, most hens don't lay in the winter.
Please don't feed your girls that. sunflower seeds should make a small part of the diet, they are very fatty.
Switch to a higher protein layer in a few weeks to help them when they start laying.
There have been multiple people over the last few days. You can look them up for everyone's comments on it. :]
Your birds are of that age that they get 'henopause', it's natural for them to slow or stop. They could switch off laying feed, try flock raiser or chick grower, they don't need the...