Thought I'd weigh in again quickly with the developments with Morty and our raw food experimentation. One of you wisely suggested I take it slowly while we get used to having a puppy around. I took that advice, and over the weeks and months of summer, slowly got bolder with trying new foods.
Now he is 7 months old. He gets about 1/2 the recommended dose of Arcana puppy food and the rest is supplemented so far with chicken wings or necks, frozen, out in the garden every morning, along with a selection of: raw egg, raw ground beef, raw small mackerel (frozen for 2 weeks first), dried tripe (can't find it fresh - wow, does it ever smell bad!), the occasional big knuckle bone from a cow, chicken livers and the occasional chicken/beef hearts. I add seeweed and nutritional yeast, raspberries, spinach and carrots for colour, haha.
The vegetables are the only things that seem not to agree with him, giving him the runs. I tried giving him frozen peas but he managed to pick them all out which was pretty funny to watch.
This seems to work really well at this stage. He's happy, it's easy. Everything is available at the local market.
I'd add pictures - he is an unusually handsome beast! - but I can't figure out how to do that on this forum.
Thanks again for all your help and suggestions here.
Morty'sMum.