Thank you all for your suggestions. MisDixie, you really know your wool!
The jackets filled one kitchen trash bag, plus one grocery bag (which is how the store determines pricing), just to give you an idea of the current volume. There is enough that I could wash half and leave half as is.
My washer is a front-loader, so there isn't a whole lot of agitation going on. Hmmm.
I'll take some pics and let you know what happens!