I did 120 last year
20 transplanted from under other trees. 120 planted from small pots. It might make a differnece if yours are a couple of years older. I'm guessing that yours are 1-3 years old and 8 inches to 3 feet tall. Mine were all started as pecan seeds that spring and put in the field in the fall.
A few suggestions:
Bare root transplanting is sometimes recommended to be done in spring, but fall is most recommended - before a hard freeze. Small seedlings from under large trees will be susceptible to a freeze damage at near 20 degrees since they are somewhat insulated from light freezes under the large branches of the other tree. In other words, move them such that they will first get a light freeze in the open instead of a quick hard freeze. Late October is good here in Tulsa.
Definitely don't transplant in the active growing season since the intense sun will mess them up.
If you know pecans much you will know that these seedlings will not make pecans until they are 10 years old at a minimum, and they will not be true to seed. If you graft them, you can get production 5-6 years after grafting at best.
You also should know that you will not be able to get the taproot since even a 6 month-old seedling will go a few feet and by the end of the second season will go down a few more feet. The taproot will be longer than the top is tall for a few years. Cut the taproot at 24 inches or less and the it will encourage the other roots to spread, while the taproot will grow back quickly. Studies by OSU have provided a lot of info on this.
Check out OSU's extension publications for more:
http://pearl.agcomm.okstate.edu/hort/fruits/index.html