Isaiah 11:8 (King James Bible) and the weaned child shall put his hand on the cockatrice’ den
In the printer’s manuscript, Oliver Cowdery initially wrote cocketrice (his spelling for cockatrice); then he immediately added a small s at the end of the word (and without any change in the level of ink flow). One could interpret the original cocketrice as evidence for the King James cockatrice’, although the addition of the final s appears to be a correction to the reading of the original manuscript (which is not extant here). Another possible explanation for cocketrice is that it simply represents Oliver’s tendency to omit a final grammatical s, especially when the word already ends in an /s/ sound in an unstressed syllable. In the one other place where the Book of Mormon quotes this passage (2 Nephi 21:8), Oliver wrote cockatrices (and the 1830 typesetter added the apostrophe in heavy ink). See the discussion under 2 Nephi 21:8.
Summary: Retain the typical adjustment to standard English in the Book of Mormon quotations of Isaiah, namely, cockatrice’s den rather than cockatrice’ den (the King James reading).