As long as she's healthy, it doesn't hurt a hen to not lay. But stopping laying is normally an indication of ill health. But keep in mind that laying is hard on a hen and is likely to shorten her life span if she never gets a break. If you don't want them to lay, just keep them with 10 hours of light or less. With nonbreeding birds, there is no reason not to give them a break. I like getting eggs year round, so I rotate light cycles and some get a break while others are laying. I do the same with my bearded dragons.