When you come across outdoor kittens, you may feel the need to immediately pick them up and bring them home but that might not be the best thing for the kittens or for you.
Some kittens may need intervention if they are not doing well. Early weaning of kittens that appear to be doing well may lead to increased mortality or failure to thrive.
If it is safe they should remain with their mother until then to learn proper behavior and socialization.
Before you move forward, consider -- Do you have the time it takes to socialize kittens?
You will have to commit to caring for them one-on-one for at least a couple of hours each day, for a period of a few weeks to a month or longer. If the kittens are neonatal, they will require even more specialized care, including round-the clock bottle-feeding.
Socializing and caring for kittens is a time-consuming process which requires devotion, patience, and attention. The decision to bring kittens into your home should not be taken lightly.
This information is from Alley Cat Allies.