Offal (kidney, lung, sweetbread, spleen) should be about 10% of which 5% liver. About 10% should be bone and about 80% should be muscle meat (including tongue, tripe, intestines, gizzards) of which up to 15% heart. Then you can also add up to 5% vegetables depending on your persuasion. I use raw grated carrot, courgette, sesame seeds or psyllium husks - not the whole 5% and not every day.
Mitchell, you don't need to worry about the 10% bone with Felini. I don't think you need to add liver either but check out the leaflet that comes with it. Felini and other complete supplements are a great first way into raw feeding with a peace of mind that your cat will get all that he/she needs. Once you are more confident it is easy to make the mix of supplements yourself or to substitute ground eggshells for bones if you feel uneasy about feeding bones or your cats don't like chewing them.
I also add about 1g of salmon oil to 1kg of meat (for omega 3) and a little salmon (for Vit D) about 10g per 1kg.
A couple of tips. If you can, get leg meat or shoulder meat - these tend to be darker than the breast meat, which means that they contain more taurine. So, for example, get more chicken thighs or drumsticks than chicken breasts.
Don't forget to feed the skin or fat of the meat. A lot of people initially make the mistake of buying lean meat or skinless chicken. Cats need fat. Lambs breast is a great source of fat and if I use lean meat, such as rabbit, then I add some lamb breast in bump up the fat content. Also try to get bloody meats - cats need the salt and iron.
Don't get supermarket minces - you don't know when they have been minced. Processing of all kinds (but cooking and mincing in particular) destroys taurine in meat , for example. Minced meat also tends to be more expensive or of the leaner kind.
Buying organic meat/free-range/additive free meat for your pets is expensive but check out Craigs Farm (be warned though - their offal is twice or three times more expensive than 'normal' offal). They do a great range of such meats including an impressive array of offal. They will get you chicken hearts as a special order.
Depending on where you live you might have a halal butcher. Many will be able to get your chicken hearts (these tend to be very allusive) and a lot stock goat meat.
The hardest part is sourcing your ingredients. Since you have Morrisons near you you will easily get kidney, liver, heart, tongue as well as lamb, chicken and beef meats. Ideally you should increase your range of offal to also include the likes of lung (a butcher is your best choice - they get plucks, which are the heart, liver and lung of an animal) and spleen if you can find it (spleen is full of iron).
And then, you can have a go at feeding whole prey as a treat - frozen day old chicks or frozen mice (from reptile shops) can be a real hit. It is not for everyone though
Hope that helps!
