how long do hatched lice remain
1 Head lice cling to hairs but stay close to the scalp which they feed off. 2  Head lice lay eggs which hatch after 7-10 days. 3  It takes about 10 days for a newly hatched louse to grow into an adult and start to lay eggs. 4  Nits are the empty white eggshells which are left when the lice hatch.