A few comments– at 20 weeks, 12 pounds in weight would indicate you're going to end up with a larger cavalier, most likely up over the 20 pound range, but that is actually a quite common weight even for show males–increasingly, breeders do not seem to be using really small male studs and most of the studs I have met are in the 20-23-ish pound range, I would guess. My Leo is only about 16 pounds at most and I have had a couple of breeders comment that they would never breed a male that small.
Breed standard in the UK is 12 to 18 pounds, and in the US is 13 to 18 pounds, so a dog at the bottom end of that scale would not be considered unusually small or petite, just at one completely normal end of the breed standard. 5.5 kg should be within breed standard and not undersized.
But she will very likely put on another pound or 2 anyway before she reaches her a full adult weight.
There can be health reasons for why dogs are small, so it is a good idea just to keep an extra eye on things When people do have a below breed standard sized dog. For most dogs, as long as they weren't from breeders who are deliberately trying to breed smaller Cavaliers (in which case they often are breeding runts of the litter and therefore are just asking to introduce unwanted health problems), being at the lower end of the breed standard or even a pound or 2 below that is really no big deal, just as it's not really any big deal if they are a few pounds over. All things considered, it is less potentially compromising to health for a dog to be larger rather than smaller because dogs do not tend to end up larger in the breed due to health reasons, but that can definitely be part of why they are smaller, especially if they are particularly small. A good breeder will not re-home a runt until they have kept an eye on it for a while to make sure it is beginning to develop normally and put on weight, and that skull plates close, etc.
Overall, I wouldn't really worry about a dog hovering around the bottom end of the breed standard, where the vet is not seeing any issues!
This, however, would potentially raise a question:
Chloe is more of a grazer and would leave her food until she feels hungry, well at least that's what we think of her eating habit. Could also be that she learn from our 8-yr old cat who has always been a grazer all her life? She is on RAW diet (minced hare mix, chicken necks and green tripes) from a local company called rawessentials.
It would really not be a good idea to leave raw food down for a dog that doesn't eat all of its food at one time. It is just not hygienic and potentially, could make a dog very ill if raw food is left out sitting for whenever the dog feels like eating it. A lot of this kind of finicky eating can be resolved by simply giving the dog 10 or 15 min. to eat and then lifting the food until the next scheduled feeding time, and not making any fuss at all about mealtimes. If a dog knows the food isn't going to be hanging around, it tends to focus the mind (as does adding another dog–there aren't many dogs that ignore their food when they know there's competition! :lol
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