My rescue pup, Sadie, is about 4 months old now. I've noticed that somtimes when she sits, either of her front legs will have this little shake. Is this something normal for a puppy? She was found on the side of the road, (and to us is perfect) but we were wondering if maybe this little shaking could be a sign of a more serious problem (i.e. the reason why someone may have dumped her.) Her front legs seem to have a slight bow, but that could just be the way her legs are built or the way she stands (she has very long legs!) 

It doesn't happen all the time, but often enough that we notice it. Does anyone have any info on this?

Cute, congrats.  I asked my vet about that also, she said it's a bird dog thing that often means they are tired.  My impression is it went away until recently, now I think he's just cold if he's not running outside! 

I would ask your vet about it.  Your pup was spayed at a very very very early age. I know rescue required it, but it was in my opinion to early and they should have got an agreement from you to spay when the pup was older.  Not your fault, but something you need to just keep in mind as the dog ages.

Anyway, I don't know if that may be affecting your puppy, but I do know with the larger breeds and especially males having them  neutered early can effect their growth and some articles indicate that it can make the dogs leggier and more prone to leg type injuries.  I don't know how true that is, but my anecdotal evidence is with my own dogs.  Belle was spayed at 6 mos as I had no intention of breeding and wanted to show her in obedience. She was only Field registered (and this was before you could get an AKC registration on a Field Registration) so in order to get her ILP (now PAL) number she had to be spayed.  My vet also thought that was the right time to spay her as well.  So I did.  She is definitely leggier than my other female, Halo, and has had a front shoulder injury (torn bicep tendon). Now I know that breeding plays a role in this as well, and the ortho vet told me he sees lots of torn biceps in hunting dogs. So, it may not be related to the spaying, but it might.  Just something to think about and talk to your vet about.

I am taking her to the vet today for her third round of shots, so I will be sure to ask then. It's good to know I am not the only one who has this problem. Hopefully it's just muscle fatigue or something. She has been growing like a weed, though, so maybe her poor little muscles can't keep up with her overall growth.

You might want to ask your vet about diet.  I have I have been told that since puppy foods promote bone growth this can cause the bones to grow to too fast in comparison to the soft tissue which grows much slower no matter what you feed.  I've talked to several breeders that stay away from the premium puppy foods and switch their puppies over to an adult maintenance food very early, especially for those pups that have that sudden growth burst. 

Re large breed puppy food, all vets, breeders and trainers I know stay clear of the large breed puppy food. The Great Dane Lady has a great article on food for puppies, puppy vs adult vs large breed and why, if anyone wants to read up on it.

www.greatdanelady.com/articles/do_i_need_to_use_a_puppy_food.htm