Have you all not noticed a difference, bag to bag previously? I posted this about 3 years ago:
Hope eats S&C and that is different bag to bag as well. The last two bags I received had rock hard patties where the bags previous had patties that were very crumbly. The use by dates are well into this year, so they are certainly fresh.
Since we have only fed air or freeze-dried food for about 3 years, I have grown accustomed to differences. Kibble, for Mick, was exactly the same, bag to bag. I attributed that to how that food is made.
I watch more for how they respond to the food. I would LOVE to have all of them on one food if I could. Hope does great on all S&C Rabbit, Eden and Ruby do not and require a mix of that and ZP.
I do continue to investigate and try (with Hope, introduction of something new is SLOW and painstaking) new air and freeze dried foods. We also have to keep her to cool proteins which means that with any brand she can have just 1, maybe 2 of their varieties.