Rescue centres are often presented with female rabbits that are either pregnant, soon to give birth to many kits, or with a litter already. This is an extra strain on the limited space for rescuing and rehoming rabbits, which can result in many rabbits being euthanased, or left in terrible homes. It is also largely, if not entirely preventable. The main causes of unwanted litters are mis-sexing of a pair of rabbits, and a lack of awareness that rabbits can breed both at a young age, and also immediately after they have given birth. The former is probably the most common situation. Rabbits may be challenging to sex at a young age. They are actually easier to sex when they are only a few weeks old, but at this stage many people are reluctant to handle them, due to the risks of the doe becoming stressed by this, scenting strange smells on the young, and potentially injuring or even killing and eating them. At 8-10 weeks , the most common age to rehome them, they can actually be very difficult to sex, and mistakes may be made. Referring to textbooks, developing experience in sexing them, and asking more experienced people for assistance is helpful at this point. Once the testicles have descended in the males, sexing is easy, but unless they are separated immediately at this stage, mating is possible. It is therefore vital to sex them promptly before 10-12 weeks, and neuter or group them accordingly pending neutering (noting that males will fight with males if housed after sexual maturity). Rabbits may mate whilst pregnant, but whilst European hares are capable of superfetation (the act of carrying a litter of 2 or more different ages, subsequently born at different times), this is thought to be extremely rare indeed in rabbits. It is far more likely that rabbits will mate either on the day of birth, or over the next few days, if left with the buck. Producing milk does not stop them mating and becoming pregnant, at all. If it did, rabbits would only have 1 or 2 litters per year in the wild, whereas they are capable of multiple litters over the summer, and are often bred in captive situations with a litter to litter interval of 35 days. It is therefore possible for a rabbit to mate, carry a litter, and give birth throughout the whole period that they are feeding a litter.