So how many of your weigh your bitches before mating, Im stressing as my bitch has onl put on 1.5lb in the first 3 weeks (20kg normally)?

I don't normally but would certainly not expect any gain whatsoever after just 3 weeks. More likely a loss from when the bitch goes off her food etc.

Nope, I know what weight they are to the nearest kg when at correct body.

Have never weighed and in whelp bitch as would not choose to visit a vets unnecessarily during that time