Researched Marguerite Henry some more, churned up a new article with a few more details about her in her old age. (p.s. who are you, "author Susan Foster Ambrose," and where is this biography you talked about wanting to write 20 years ago; I have wanted one to exist for almost that long)
Re-remembered that the U of M's Children's Literature Research Collection has a magnifient collection of Henry papers and I really, really need to make a plan to see them with my own eyes and grabby hands. These include 8 (!) titles listed under "unpublished works" and I am desperately curious to know if they are just notes, or partial manuscripts, or actual entire drafts, because the latter would be an actual wish of mine granted.
Re-remembered they also have Lynn Hall papers; not as extensive but still -- notes & correspondence on any of her amazing stuff? Yes, please.
Discovered they also have small but nevertheless pertinent collections of manuscripts or other ephemera for such classic animal book authors as*: Alice O'Connell (Pamela and the Blue Mare, that rarity), Jim Kjelgaard, Barbara Corcoran, Wesley Dennis (looks like art only though), and Rutherford G. Montgomery. That's not even exhuastive; honestly, I could feed authors into this search engine all day. The database shows 1775 collections.
(*Not, tragically, my other most beloved horse authors Dorothy Lyons or Jean Slaughter Doty, though, nor Albert Payson Terhune. There's no reason they should have them, really, but when they turned up with so many of my other faves I got greedy.)
[INCONVENIENTLY: they are literally only open during business hours (M-F, 8:30-4:30pm), only staying open until 7 a couple of those days, which means boyfriend can't drive me* and I would have to either figure out & pay for parking garage parking ($3-12/day if I can get in the campus lot...which is probably easier in summer) or take the bus, both of which are terrifying prospects, on top of having to either work out a Monday where I can square away contacts early, or take a day off.
* Wait. Boyfriend absolutely COULD drive me if I bribed him very nicely to get up extra-early, go a few miles out of his way and drop me off before he went to work! Or possibly we could make a whole day trip out of it and go together; he could find something to occupy himself and we could go to dinner after it closes. I will ask him.]
Found an awesome special buy at the dollar store: 3-oz. cassava pop chips. Those definitely cost more than $1 everywhere else and are second only to baked potato chips in terms of Best Snacking Chip. Low fat, delicious "luau BBQ" flavor, super satisfying.