Premium Feather Member
If the coop stays dry dampness should not be an issue. Since my chips are stored in a pile directly on the ground they're always a little moist when I put them in the coop, but they dry out pretty quickly and so the moisture isn't an issue after a few days.
Splinters could be an issue, I suppose, but all the birds I have with bumblefoot are heavier birds so I think it's more the impact coming off the roost onto the bedding that causes issues. If your roosts are high that could be something to think about.
OP asked about wood chips, you're mentioning shavings.
If you're using wood chips, use whatever mix you have available. My chips are a mix of cedar, hemlock, fir, and... anything else that got in the way. Black walnut and Eastern red cedar are probably the only two that I'd recommend caution on (black walnut is dangerous to horses and can kill other plants if used as mulch, Eastern red cedar is highly aromatic so would need to be aged thoroughly before using).
As far as cedar in general, you'll get mixed responses. I feel very comfortable about using it in my set up. We have Western cedar which is lower aroma than Eastern red cedar.
I would probably avoid using all cedar, or fresh cedar (well, fresh anything really... pine sap is awful!), or cedar in closed-in environments (i.e. indoor brooder, coop lacking in ventilation). My coop is well over recommended ventilation plus has a high ceiling for added air volume.
Many coop builds have cedar and I don't think people ever consider that. My current coop has cedar trim, my old one (which is now a chick brooder) is 100% cedar.
Obviously if you're not comfortable with it, don't use it, but I've been mixing in cedar for the last few years and there's been no sign of respiratory issues in my flock.
IMO, the Eastern vs Western cedar is an important distinction.