Are you sure they aren't laying somewhere other than the nests?
I don't put much stock in the squatting thing. I haven't had a hen squat for me in years and have had thousands of eggs.
Try the pelvic bone space check -
https://www.backyardchickens.com/articles/who-is-laying-and-who-is-not-butt-check.73309/
It is rare for a pullet/hen to never lay but EEs can be all over the place since they aren't a true breed. Some lay extremely well and some infrequently depending on the line they come from.
Weather really has no effect. Day length is the big determinant. But since yours are a year old, they should have reached point of lay by summer solstice last year.
What we really need to know is what makes up their entire feed intake. Feed protein %, calcium %, any treats/scratch/scraps and what % of the diet those things make up.
If they aren't hiding their eggs, hopefully they haven't been fed layer feed this entire time since last summer.