Snipe, thanks for posting your experiment.
I am sure the Pond Boss professionals understand your project design, but (if possible) can you expand on a few points during the course of your experiment, so the rest of us can follow along?
As regards question #1, does the term "accept" mean some fish will elect to eat the pellets and some will not?
Or some will "accept" on Day 1 and some will "accept" on Day 10? In that case, it could be possible that Feed X resulted in more weight gain for the fish that were early adopters (relative to Feed Y), but that the distribution of "time to acceptance" was skewed much earlier for Feed Y - therefore it is the "better" feed for overall BG weight gain. (Is that part of the hypothesis that you are testing?)
Will you also have some type of control group that is the same starting size and age distribution in a grow-out pond with only those BG plus forage? (I assume there is no way to have a control group in the floating cage pens that can still have a proxy of a "natural" diet?)
I also don't get your reference to "not addressing liver function", but that is due to my low level of personal knowledge. If it is important to understand, can you clarify for us Noobs?
Good luck on your project. It sounds like it should be a Pond Boss hot topic!
