There are lots of things that can cause a hen to lay inconsistently or stop altogether. The breed: Some breeds only lay 3-4 eggs per week. Even with the best layers, you can't expect an egg every day. Age: New laying pullets will sometimes take a while to get into the swing of it. Some older hens will slow down as they age. Molting: A hen with a severe molt may stop for weeks and can be inconsistent when starting back up. Stress: A move to a new coop or home, new flock additions, or a predator scare can cause laying to stop briefly. Broodiness: When a hen gets the urge to hatch eggs, she will sit on a nest, often cease laying, and may stay this way for weeks. Some breeds are broodier than others. Winter darkness: Some hens are quite sensitive to the lack of light during the winter months, and many stop laying for several weeks until the days begin to lengthen.
Of course there are medical problems that cause egg laying to stop. Look for other symptoms: lack of energy, disinterest in food, poor breathing, discharge from eyes or nose, bloody poop, evidence of mites. Feel her abdomen down low under her legs to see if you can feel an egg. I think if they are egg bound they do not act normally.
There are lots of scary things, but considering you just got her, I would expect she's just taking a while to adjust. How old is she and what breed? Are there others, or just the two?
