Hmmm...just looked at the site and those mommas are pretty small.
4 pounds? 3 3/4 pounds? Also makes me wonder what age she places the pups...we all know that 12 weeks is the standard age for Yorkies pups, but she talks about what to do 'until they are 3 months old' and the contracts says you have to take possession of the pup by the time they are 12 weeks.....hmmm....just a few things to watch for.
I find the most trustworthy breeder the kind that you can develop a good non-business like relationship. If you feel like you have found that, like what you see, etc, then you have found your breeder.