Coop Floor/Bedding

Hello- new chicken owner here! We have 6 ladies that currently have a coop in an old mini pony barn/shed that my husband converted part of. The flooring is just dirt with straw for bedding. From what I understand we should NOT use straw and instead use pine shavings or similar? We have easy access to straw due to my FIL being a beef farmer, but none of us have ever raised chickens. We’ve only had them for about a week so I want to correct any mistakes/prevent issues asap.

Is the dirt flooring ok? Or should we have something else under the straw? Should we remove all straw and replace with pine shavings? Anything else? Idk why but my biggest fear is mites/lice 😬 I have two young kids and a dog and I don’t want any issues with those kinds of pests!!