I always shove everything in, liver and all. Yes it may mean you have to sieve it through a fine sieve if you don't like the bits, but we don't mind. Extra protein!
I do stock from carcasses separately, as it tastes different and can be better for eg gravy. Also carcass stock, once you've boiled it to death, sets once cold thanks to the gelatine from the bones and cartilage. Giblet stock stays liquid.
Good luck Impy and here's to some great soups or stews!
See, that's the thing, I have no dog or cat to eat 'em, and even the Human Dustbin DH would turn his nose up at giblets. So, as I hate throwing stuff away, I have to make stock with them
Moonbells DH was highly amused the day I returned frm the butchers with a groaning shopping bag. 'What've you bought??' he says. Well, I say, I've bought 6 chicken thighs and some mince, but I've got a bag of chicken bones for stock, a bone for veggie friend's dog* and and a big lump of suet and those were free.
* Veggie friend approves of dog eating bones, as it is a carnivore, but cannot handle meat so I am the dog's dealer...
I always ask for extra giblets from the local shop because so many people don't want them so I get them for free.
Stick them in a lidded pan with a roughly chopped onion and carrot, half a dozen or so whole peppercorns and a bay leaf, and cover with water. Stick on to cook, and simmer on lowest setting for as many hours as you like (I try and go for 3-4), checking water levels occasionally. You want it to reduce to about a pint. Bin the bits as they'll have lost most of their flavour into the water.
Strain and put liquid in a jug to cool down, and then put in the freezer in a ziploc or similar (though do check the seal!). When we want some soup or a stew, it's easily melted. Could also do in icecube trays for if you just need a flavour zing in something like rice or pasta.