5 months - still really small?
 

My GSD boy just turned 5 months, and he only weighs 42 lbs. He is pretty skinny and doesn't eat a lot. His parents are both pretty big, around 100 lbs. We used to feed him Acana, then switched to Now! because of the protein content. He didn't seem to like Now! so we are currently feeding him Performatrin Large Breed Puppy. We follow the guidelines in giving him 3-4 cups a day, but he doesn't always finish his food. He wasn't the runt of the litter either, so we are pretty confused. Perhaps he will get a growth spurt soon? Did anyone experience something like this?

I don't really have any advice to give. Except that my female GSD was on the smaller side til she hit 5 month's than she hit a huge growth spurt. I mean i look at picture's of when she was 4 months to 5 months and it's a huge diffrence.(She's almost 8 month's now) So, he could be getting ready to hit a growth spurt. All puppy's grow diffrently and I wouldn't worry about his weight or anything if he look's good and act's like a puppy :)

I should add she was the runt and so much smaller than her brother that a friend has, and now she is about as big as he is! But she is a pretty big GSD now lol

That's true. I just came back from the vet and he told us not to worry as well. He still also has all his baby teeth, so many he hasn't hit his growth spurt yet:confused:
The vet was a little concerned with his thinness though, and he suspects it could be worms. So we got some medicine for it, and hopefully he will put on a little more weight soon!:p

If it is worms, and he kills all them suckers, you will be surprised how fast the growth is.