Anna "Chickadee" Cardwell's battle with cancer was something that was well-documented, TMZ has learned ... and will be shared with fans in an upcoming season of Mama June's reality series.

Family sources tell TMZ ... Anna was very open about her health issues, and wanted it to be included on "Mama June: From Not to Hot" so people could better understand the struggles she went through, and those of cancer patients, in general.

She also wanted fans to know everything she faced, since she was always candid with them.

We're told Anna had no problems with the production team filming her journey, and the crew was by her side just hours before she passed away -- Anna was in hospice for a little over 3 weeks toward the end, and she was open to documenting everything.

Sources say production felt it was best to not be there when she passed, and they won't be there to record the funeral, either ... despite Anna being alright with it, the crew wanted to give the family some privacy while they mourn.

As we reported, Anna was suffering from stage 4 adrenal carcinoma and died on Saturday -- we were told Anna requested that her fans be able to attend her open-casket funeral, and our sources say the family's honoring that as one of her last wishes.