1 of 4 hens not yet laying

We have 4 Ameracauna/EE hens who just turned a year this week. They all stoped laying completely from mid-December to the end of January. We had no problem letting them rest and conserve their energy for more crucial things, like staying warm. Then they all had a molt in January, which scared the daylights out of us b/c they're outdoors and it was ARCTIC up here in North Central Massachusetts! Finally, end of January, Fuzzy layed our first egg of the season. The others followed suit, though not regularly, as we expected. The problem now is that we haven't gotten an egg from Fuzzy since February. They each have their own distinct egg color, so I know who lays what. Since March, we've been getting anywhere from 1 to 3 eggs from the other girls, but nothing from Fuzzy. She appears completely healthy, acts fine, doesn't appear to be molting. I've searched every inch of their yard, and not found any sign of her laying elsewhere, not even a piece of her tell-tale turquoise egg shells. I've felt her belly (much to her disgust! How DARE I?!), and feel no lumps. Everyone else is laying fine, and they all eat the same stuff. Any ideas?