First vaccinations should be given by the time they are 8 weeks of age. If the mother vaccination status is unknown then 6 weeks would be an optimal choice for vaccination for the kittens. Because they are now eating solid foods mom will start weaning them from the teet gradually. It is recommended that they stay with mom until they are 8 weeks of age and should be completely weaned between 6-8 weeks. If you are able to and willing to keep them around mom until they are 12 weeks then this will be wonderful for their socialization and development because they will learn a lot of things from mom that we cannot teach them ourselves. The average however is 8 weeks.