Nine Days Old!
If you’re watching the riveting viewing that is the puppycam (trust me, it gets more exciting as they get older and more mobile), you will see that occasionally Jim or I move puppies around while they’re nursing. While I generally try to interfere as little as possible (other than by rescuing puppies who get stuck behind Alice under the pig rails or whatever), if we have a puppy who didn’t gain as much as the others, we will try to place that puppy on the inguinal teats (the ones closest to Alice’s back legs) preferentially. In general the inguinal teats seem to let milk down faster and easier and this can help the puppy catch up. In the big picture it’s pretty normal for them to gain more or less each day and as long as the overall trend and average gain are going the right way it’s not a concern, but much better to be proactive anyway in my view.