I am experiencing a similar problem, but with a hopefully helpful background. I too have 4 pullets all hatched this last spring. My normally best layer, a production red has not produced an egg for about 4 or 5 days now which is highly unusual.  Here's the thing, about a month and half ago I noticed her behaving very differently. She was lethargic, yet didnt' want to lay down. She would just stand with her feathers, particularly in the back fluffed up. She was clearly - different than normal. I also noticed her looking like she was flexing to try and produce an egg. From all this behaviour I determined she was egg bound since it was late in the day and she hadn't laid. I did the warm bath and sure enough she produced not only one, but another smaller attached soft shelled eggs.
Now her not laying is very different. She seems very normal and it has been like I said, several days. I am not sure that even though they don't go through a full molt (she hasn't been losing feathers, but her feathers are less shiny and her comb is not as red) I think the time of year is still bringing on her hopefully temporary stopping of eggs. She eats, she drinks, she pecks, she runs, she acts completely normal - just no eggs. So I guess my lengthy answer is, I think you would notice a change in her if she is egg bound, given you are one to really pay attention to your chicken's behaviours, so I wouldn't necessarly force the bath situation. And other than that, if she is acting and looking healthy, wait it out and let nature kick back in when its ready.
Good luck and hopefully we'll both have an egg from the one who's not laying soon.