On the time to transplant, we would say NOW. Some bluebonnets will be blooming in February, especially where you are, in Southeast Texas. The more quickly they get (carefully!) taken out of the ground and put into their new location the less damage will be done to the roots or by dehydration.
As it happens, this is not a new subject for Mr. Smarty Plants. Please see this previous Mr. Smarty Plants answer on transplanting bluebonnets.
This USDA Plant Profile Map does not show Lupinus texensis (Texas bluebonnet) growing natively in Colorado County. However, it does show them growing in counties all around, so we are guessing that they grow in your area, but just have not been reported.
This, however, brings us to another subject. Consider where you are going to find the plants to move - is it in your immediate area where the soils would be compatible and do you own that pasture or do you have permission from the owner to take those plants? This may sound like real nitpicking, but taking anything, including plants, from any property - whether it is owned by the Federal Government, State Government or is a wildlife preserve - is considered a felony. You may look out at all those fields of wildflowers and consider that because you can see them, you can transplant them, but that is incorrect. We would say that most landowners would be happy to let you take a few plants for your own garden, where you will be able to propagate more, but we wouldn't count on it. Furthermore, the State Highway Department frowns on plants being removed from roadsides, both because they want everyone to be able to see these beauties, but also because of the hazards of stopping on a roadside, both to the stopped vehicle and its occupants and to the other cars on the road.
Below, from our Image Gallery are several pictures of newly sprouted bluebonnets, to help you dig up the right thing. We also suggest you read our How-To Article on How to Grow Bluebonnets.