Switching to Layer

They should be on starter until they AFTER they start to lay. You (and your hens) will  want those first eggs to be smaller and easier to pass! And besides they might not lay for a few more weeks.

Maybe you can put an ad on Craigslist to see if anyone in your area has a partial bag or wants to split the cost of a new bag with you?  Or you could just buy a small bag and keep using the starter and add calcium on the side until it's all gone.

BTW I am not sure why you should discard your first eggs.
 

When I ran out of my last bag of starter crumbles my pullets where about 21 weeks old and had not started laying, but they had the real red comb and large wattles and had started squatting... so I switched them to pellet layer feed.  I'm not saying it's the right thing to do, but it hasn't caused problems for me or them (I think). They learned to eat the pellets and now love them. They were on the pellets for about 2 weeks before I got my first egg and it was a small little egg.  They've been laying now for about 6days (with one day skipped) One sex-link and one Buff have started laying.  They are smallish eggs. No double yolks or anything. Kind of what they call "fart" eggs here. lol 

Someone could give you better information than I though. Hope you get that first egg soon!!!

No need to switch, stay on the starter but switch to non medicated if you're still using that.  Get a bag of oyster shell (only around $4) and put it in a old chick feeder in the coop.  They'll take it as they need it.  I read that not only does layer not have enough protein for growing pullets but the extra calcium is too much for the ones that are not laying yet as they have no way to rid their bodies of excess like a laying hen does.  I won't switch to layer until all of my girls are well into lay.

I would agree with sticking to a non-medicated grower food until all of the girls are laying and add the oyster shell for calcium on the side. The birds will only eat the calcium if they need it. For the non-layers calcium can build up in their system and potentially be harmful. (They might start laying soon and be fine but why risk it?) The grower food with calcium on the side will not cause any problems for layers so you will be in good shape even if they all start laying right away - just make sure they have that calcium on the side or they will lay eggs without shells. This is also a good solution for mixed age flocks.

Once pullets are 18 weeks old, buying ANY feed would be just fine.  Non-medicated Starter, Grower, Raiser or Layer.   

There's nothing magical about Layer.  It is merely feed with high calcium ground into the feed for the flock keeper's convenience.  This high calcium content is potentially damaging to young and adolescent birds, but is just fine for any pullet at 18 weeks or older.  If Layer is not fed, then a calcium supplement of some kind needs to be provided on the side, which the birds will partake as they sense a need.  Simple.

I switched mine after all my hens were laying and I finished the bag of chick starter first.

I start feeding mine Layer earlier than what you guys are talking about. I feed starter until about 8-12 weeks, then grower until about 16 week, I guess. Then to layer. I just go by size, comb redness, etc. None of my pullets have ever laid big first eggs or anything. They have been fine. I play it by ear, I have no set age that I switch them to different feeds.