Could be???
I have not seen a snake in a while but I know they are out there. Be careful poking around. Don't let sometime surprise you!
I really would have expected your girls to be giving you a few eggs through the winter. My 6 pullets, born around May 1 are laying as well as 3 1.5 yr old Wyandottes. I'm getting 4-6 per day.
I will say some breeds are less likely to lay in winter. I've raised 2 groups of Cream Legbars from 2 different sources in 2 different years. Some are 3 years old, some are almost 10 yrs old. Both groups started laying late summer/early fall of their first year. Both groups quit laying that first winter with no molting. They both started back laying early Feb. They lay like crazy spring and summer but no winter eggs. The older ones still lay a few each year in spring.
I really would not expect this laying pattern with Speckled Sussex or Dominique.
Now an 'Old Wives Tale'....

Collard greens and cayenne. Old lady swears it will help them get back to laying. Who knows???