Does your company use all in-house developers, or are some of them freelance? When you are working with freelance developers you have to make sure they provide the same quality product and have strict rules for meeting deadlines as you would expect from your in-house staff.
Finding a good developer or a development team is not an easy process. You have to get as much portfolio work from them as you can, then decide on the quality whether you want to work with them. Once you made the decision it is best to test them out on a small-size project first. If they meet your quality criteria then send them out on a larger project.
If your developer starts lagging behind, it is best to immediately replace them. By allowing them to continue to work on the project, you are risking the stability of the relationship with your client(s). It is best to make sure that the project gets done by any means necessary, including replacing the developer who worked on the project from the start, and having a new development team knock out the project in time without any bug delays so your client comes back for repeat service.
If you just started your web development company, the above may not be something you know. You can end up learning the hard way. But if you are reading this then I hope you take these rules to heart. Your success depends on how effecient your team operates.