Yes, mostly.......moisture and heat from initial decomposition can cause molds, already growing in normal and balanced populations on the bark of trees, to grow to toxic amounts.
The main one is aspergillus.
Sounds like landscaping mulch, and yeah they are smaller and I wouldn't want the dyed stuff.
I believe the only place to get ramial chippings is from a tree trimmer. You'll need to have a place to dump a large quantity. They are usually happy to do it so they don't have to pay to dispose of...
'Ramial chipped wood' might the term you are thinking of,
but not sure the tree trimmers use it.
If chippings are fresh and have lots of green leaves included it's best to let the pile sit for a few weeks, then scrape the outer layers of pile and add thin layers of that to the run.
Can help to...