Advice on weight please?

[hellhasnofurylikeahungrywoman]

DDog (8-12 month old cocker/sprocker/some kind of spaniel) was adopted by us two weeks ago, he's an underweight boy and we are trying to get some weight on him. I have been feeding him double rations but he has only gained 50g (he was 10.45kg and is now 10.50kg), he has been checked out by at least two vets and no-one has found any problems. His coat is in good condition and his energy levels and appetite are normal. RAW fed, using lots of tripe now to try to increase weight. How long do I leave it before I start to get really concerned?

How easily can you feel his ribs when you run your hands over them? Did the vets say he was under weight?
I ask as my cocker cross spends most of the time at this weight and is not underweight.

My vet told me my dog was underweight a few weeks ago and we tried feeding him more but all that happened was he poo'd twice as much as usual (and it was horribly soft) and he was even fizzier and only put on 300g (vet wanted at least a kilo). However he's been on restricted exercise for the last two weeks - and possibly for several more - and he's finally gained so is now at his goal weight. He is normally very active and burns anything extra off. My sister's spaniel cross (mostly springer) was really thin until this year (she's now 6) as she just used up masses of calories. She's not fat now but just has a little more rib coverage

My setter was ribby until he was two. Still is if he decides to skip a meal. If two vets have declared your dog healthy, I wouldn't get concerned at all.

My working cocker looks like a famine victim. You can see all of his ribs and all his back bones. He runs around like a loon for 2 hours a day. Eats plenty, Coat is glossy smooth. He's happy. I have given up taking any notice of what folk say about him.

Trouble is, I think (a bit like humans, if I dare say that...) we have an incorrect perception of what is a normal weight, particularly for some breeds.

Ddog2 is still thin, but not as thin as folk think he is iyswim?

Vet does say he is very thin. Every rib, vertebrae and bone is prominent, he has no fat cover. Our collie is slim, you can feel her ribs, she has a definable waist but the spaniel takes it to a new level of skinniness. I am just slightly concerned there maybe an underlying thyroid problem but because we don't know what he looked like before I don't know if he has always just been a super skinny dog or what his normal weight looks like. I think it's less the skinniness that worries me and more the fact that he has no muscle coverage.

Building up must be done slowly - doubling rations is too much too fast.

Increase gently and get his system used to processing more food - chucking masses more at him quickly will result in an upset tum and masses of poo.

Gentle, regular exercise will help build muscle - swimming would be brilliant to start with.

What raw food does he have? Maybe could try stuff like lamb or duck that is fattier? A couple of eggs a week, oily fish?

My collie was thin until he had his nads taken off. Now he's his ideal weight. I have an 18 month old mini dachsie who is also very thin but I have to keep him that way for his back, so am contemplating leaving his nads on. Anyway, I give the dachsie sardines/mackerel in oil 'sprinkles' round the garden 3-4 times a week, gives him an interest, extra cals. He's very glossy and keeps up with the collie on walks.

He's on a green tripe and chicken/turkey mix at the moment, I use Natural Instinct. I did wonder about adding some fish in too. He had his bits off just before he came to us so maybe that will help.