Ok, first off - don't freak out here lol - even though the scale at your work is calebrated and correct, maybe the one at the vet office isn't. Just because a scale is at a vet office doesn't necessarily mean it's perfect. Dogs tromp and stomp on those things
. The clinic I worked at, we calebrated our scales about once per week and even though they were digital, they would still be off by a few ounces sometimes.
If you take them to the vet and they have in fact lost weight, your vet can guide you from there about whether or not one or both of them needs to gain a bit back, if so, you'll just up the food amount a bit and monitor them. Switching to a raw diet probably eliminated some calories if they were on kibble before (especially if it had grains in it). Don't worry, just see what the scale at the vet where you got their original weight from says and go from there
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