Lice eggs hatch between six and nine days after being laid, according to the CDC. The eggs (called nits) can be hard to find due to their small size and are usually white or yellow in color.
When the nit hatches, it releases a nymph. Nymphs are comparable in size to a pinhead and mature in about seven days by going through three molting stages. Adult lice grow to the size of a sesame seed, and the females can lay up to eight nits in one day. Adults live for around thirty days and need to feed on their host’s blood daily, says the CDC.