Longfellow's The Sermon of St. Francis (if you use it please let me know what tune you used).

Also, I have a small hymnal (text-only, about 40 pages) entitled Hymns for Creatures Great and Small, © 1997 and edited by British Christian animal-rights activist James Thompson. One of the hymns is at the (American) Hymn Society site. I can post others if anyone's interested.

Haruo