I have 7 slings of different species, most under 2 inches or so. They are all Brachypelma or Aphonopelma species. I know that they both have urticating hairs. My question is when do the urticating hairs start to develop and when do they start using them as a defense? I know this will depend on size, age, species, etc. but just wanted a general guide line of what to expect.