Err... yeah sure, but you have to understand that pixar has a department of shader writers at their disposal, not to mention the fact that they make their own rendering software thats hands down the best, and fastest rendering tool ive ever used for 80% of all rendering jobs out there.
Also ist not just shaers its also ligths and they have departmen dedicated scene lighters too at their disposal + artists. Not impossibly hard but requires a few uni courses of math and CG theory to attain the level of ONE of theese jobs. But yes not imppsibly hard just the procedurals/lightning rigs are a bit timeconsuming to make.*
Which shader to be precice.
Just out of curisoty toystoory 1 2 or 3? I mean 1 is pretty simplistic tough has a tad bit complex procedurals, 2 is allready VERY complex indeed.
*pixar releases reseach papers that pretty much describe their coolest shading codes so just go up and read what they did. Justa word of warning, it takes me reoutinely 2 weeks of fulltime work to replicate the papers on the average, converting the theory into maya functionality without prman is not so easy. And thats 1 simple shader you need hundreds of them.