Hello...Usually, what matters is the content. You can have several blogs on several subject matters. Duplicating a blog over several other blogs may attract penalty from google serps. Make sure that the blogs discuss different subjects. For example, you can have a blog for each product or service. But, you need to discuss the product or service in depth, when you have different blogs. Finally, it takes a lot of time to update blogs. It is good to have only a few well maintained blogs rather than having several blogs that rarely get updated.