Not sure if this is the right forum to put this?

My tripawd is a 50 pound Border Collie/Newfoundland mix w/a right front amputation.  She's currently on Zignature lamb: a limited ingredient diet free of chicken, corn, wheat, soy and potatoes.  Supplement-wise she's on Nordic Naturals Omega 3 Pet,  Herbsmith's Microflora Plus, Kelp Products of Florida Granular Kelp, and Sound Dog Viscosity Powder.

I recently switched to the Sound Dog Viscosity Powder from the Synovi-G4 "highly palatable" soft chew which:

• she hated so much that I had to disguise it in peanut butter, because trying to mix it into her food, only got me gooey soft chew bits hidden around my house, and even then she'd sometimes work the soft chew bits OUT of the peanut butter
• listed 'dried poultry liver' & wheat flour as ingredients

Now, the SDVP has higher amounts of Glucosamine, HA, Chondroitin So4, MSM, Boswellia, Curcumin, and Corydalis, which is great, BUT I've noticed her being a little more itchy since switching.  One of my coworkers recommended putting her on Nupro Joint & Immunity Support, and while looking at the ingredients, it seems like I'd be able to be able to cut all her other supplements out because the Nupro appears to be all inclusive?  Can anyone tell me if that's true?  

I'd also appreciate any recommendations on other possible grain-free joint supps.

Thanks in advance, 

Roxy & The Slightly Itchy Miss Trinity