10% is 10% regardless of the total weight!
It's lovely to hear that Bracken is enjoying his new diet. As this is his third week you can now start introducing other meats and offal and maybe some oily fish too. Try one new protein source at a time just in case you find one that doesn't suit. My 2 eat pretty much everything but they weren't keen on liver, kidney or oily fish at first, so I used to sneak a little bit in to help them get used to it. My friend's Golden Retriever turns her nose up at duck and just refuses to eat it, presumably she just doesn't like it.
If you aim for roughly 80% muscle meat, 10% bone and 10% liver/kidney over the course of a week, and feed a variety of meats, you should get the balance correct. If you find that Bracken becomes a bit constipated feed a bit less bone. William doesn't cope with as much bone as Louis so sometimes Louis might have a chicken carcass while William has boneless chicken. I also add some raw, blitzed veg. to their food sometimes, mainly to help ensure William doesn't become constipated.
This is roughly what I feed over a week, just to give you an idea of what (I believe) makes a balanced and varied diet. I feed 2 meals a day -
1 meal lamb or ox heart.
1 meal oily fish. I feed sardines or sprats when in season, but if I can't get raw oily fish I'll feed tinned sardines or pilchards after draining off the oil or tomato sauce.
1 meal chicken foot and boneless chunks of beef or chicken or lamb and some liver or kidney
2 meals green tripe
2 meals beef or chicken or lamb chunks with liver or kidney
7 meals Natural Instinct minces, various types, with bone in
Sometimes Louis has a duck neck or chicken carcass instead of NI mince and William might have a chicken wing with some bone free meat.
This evening they're having something new to them, goat mince with liver and kidney added.