Keep in mind that 15 chicks = 60 sq ft in the coop and 150 sq ft in the run, if you have not already discovered this. You will want the coop ready within 2-3 weeks of arrival if you brood indoors, or sooner. And you will want the run ready a few weeks later, if you will have one.
You might check out storage sheds on sale or reduced price demo models.
You might check out storage sheds on sale or reduced price demo models.