Depends on the Vet cropping but 8 wks -6 mths is average. I know of breeders who will have them cropped as early as 1-2 wks...But if you are taking them into a facility you are risking the chance on picking up something that may infect the pups! Again its best to check with your Vet. because it is up to them, and some have no issues with cropping an adult.