Hey there!! I also do a little bone collecting, but it’s more of a catch and release type of thing, I don’t keep them.
I live in mid Missouri, so we have a lot of woods nearby. If you’re looking for mammal bones, I highly recommend forests known to have coyotes, coyotes will leave bones around their kill-sites and where ever they are the animal, and usually those are in pretty good condition.
Or, look for owl pellets! Kinda gross, but usually there are intact rodent bones inside! If you’re lucky, you’ll find a whole skull!