If you bring soil in from another area it may have strains of coccidia in it that your chickens do not have resistance to, so you may see an outbreak of coccidiosis if you do this, although in a dry climate like I assume you have, it may not be a problem.
I would entirely agree with @nminusyplusm though and encourage you to deep litter. It makes the earth so much healthier (which can also make the hens healthier) and you get the benefit of compost for the garden and your girls will love raking through it to find bugs etc. It takes a bit of experimenting to figure out what components work best in your climate, so don't expect to get it right first time, but keep experimenting with a mix of different litter materials. I use a mixture of dry autumn leaves, chopped hedge/tree cuttings, straw, grass cuttings, spent bedding and manure from my horses stables etc. Once you look around for materials, it is amazing what you can find for free that will dramatically improve the soil structure and composition. I agree that breaking the current surface up with a pick or garden fork first will be an important step before starting to add litter.
Good luck with it.