On average, most queens give birth to 4-6 kittens (although some can have as few as 1 and some can have as many as 12) in a single litter. The queen will typically spend 15 to 30 minutes between each kitten, pushing and resting in between each contraction. The entire birthing process can last anywhere from 6 to 12 hours, depending on the number of kittens in the litter.