iPad message app problem

I Have two IPads One is a three and the other is the pro model. I also have an iPhone 5s. At first all three devices could send and receive messages. Now only the iPhone can send and receive. All messages on the iPad's disappeared. When I try to send a message on either iPad and I pick the name to send it to it appears in red type. The iPhone name appears in green type. sure could use help,figuring this out.