Congratulations on that first egg, sorry it got eaten, hopefully she will lay the others where she is supposed to. Have you seen her checking out the nesting boxes? Pullets a lot of times don't really know what is going on and will lay their first eggs in various places or just drop them randomly, even if they were rummaging in the nesting boxes before... most of the time they do figure out what to do pretty fast. Make sure your next boxes are attractive to a chicken, dark, secluded, fake eggs, easy to get into, plenty of bedding etc. You could try keeping them locked in the coop in the morning so they aren't running around outside, especially if you see a pullet thinking about laying.
One broken egg found outside shouldn't turn them into egg eaters, but obviously I would try to avoid them getting anymore...
