Given that women replace shelo asani isha with she'asani kirtzono, is there any halacha on what a Jewish slave would say for shelo asani eved? Also, would a slave need to be need to be acquired & held according to halacha to be considered eved, or would a Jew forced into slavery by gentiles be considered eved for the purposes of halacha?
(In case you're wondering, this came up during a conversation about forced labor in concentration camps during the Holocaust.)
השבוי מברך שלא עשאני עבד שלא תקנו ברכה זו מפני העבדות עצמה, אלא מפני שאין העבד חייב במצות כישראל ואינו ראוי לבא בקהל ופסול לכמה דברים.
One who is captured blesses "SheLo Asani Eved" for [our sages] did not enact this blessing because of the work itself, but rather because a slave is not obligated in Mitzvot like a Jew and is not eligible to [marry] into the [Jewish] community, and is invalid for some things.
From this we see the slave under discussion is an Eved Kena'ani not an Eved 'Ivri (who is obligated in Mitzvot like a Jew). Accordingly, Jews in forced labor camps in the Holocaust (for example) would still have needed to say this blessing. An Eved Kena'ani would seemingly just omit the blessing.
When I went to Poland with my seminary, my Rebbeim spoke about this topic. Jews in the holocaust would question whether or not they should continue saying this bracha, to which thier Rabbeim told them- A Jew is never a slave. We're only considered a slave when we surrender to our yetzer hara. We always have an opportunity to serve Hashem whether it's easy or difficult, and that's something that could never be taken away from us. Even in the holocaust where Jews were physically treated as slaves, their choice to serve Hashem was never taken away, and therefore they were free, and we continue to be free every moment we serve Hashem. Although we might be physical slaves, or slaves to Hashem, someone who's a slave to Hashem is always free. Ani avdecha ben amasecha pitachta lemoseira- By the fact that we're His servants and we're bound to Him, that opens up everything for us and frees us.