I just noticed that you had some stuff like 'brown' several times. You can put a ^(number) at the end, and it will increase the probability. Like instead of having brown in there 3 times, you can save space by adding ^3.
Also, your fur and pattern system is more complicated than it could be. You can just add in a color section and have the output be something like ' {spots|mask|stripes}'.
Sorry if I sound rude or something, I just want to help!