I think that the pitchers may not last as long with fertilizer in it. But the plant seems to grow well as SFLguy said. But from reading about more about Nepenthes, higher nutrient availability (in roots) could reduce the rate of pitcher initiation in some species.
SFLguy, I like the nice pink color of your N. veitchii! You mean 1/4 tsp per gallon of fertilizer (something like 20-20-20) by "1/4 strength", right? Do you root-drench the fertilizer or do you put it in the pitchers? I'm doing both. For root, I do something similar to orchids, but less frequently; 10-30ppmN fertilizer including inorganic fert. and fish emulsion, some humid acid, and kelp products like MaxiCrop at 1TBS/gallon. MaxiCrop can increase the EC quite a bit, but I think it is still under 300 microS/cm (150ppm or so of TDS). For the pitcher, I use the same, but also I use Osmocote Plus. I think I rotate one fertiligation with 2 pure water irrigation or so. There isn't a lot of information about Nepenthes root-fertilization (unlike here in ST). People in CP forum talk about the Maxsea, but the manufacturer doesn't supply the enough information, so it is a bit sketchy.