I had 3 pups born last Friday all went very well

I have one that although gaining, isn't gaining as much as the others, she isn't weak and doesn't need any help in latching on or staying there, feeds the same time as the others and is as active as the others, I make sure some of her feeds are off the back teats too

Here are their weights

1st pup born 8oz...Day 6 11oz
2nd pup born 10oz...Day 6 17oz
3rd pup born 8oz...Day 6 16oz

Would you be concerned ?  Don't know if it matters but Pup 1 is the only girl

Thanks
Lydia :)