3 reasons: 1. As Eliot says, "bring" does not necessarily mean "carry". 2. If you use 'brought .. from.. to Silbury", it infers that the writer is located at Silbury, whereas using 'carried' indicates simply that a mesage was transported between the two places. 3. In English, the verb 'to carry' is, in the context of the use of birds to transport messages, normally associated with pigeons. The trained birds are usually called 'carrier pigeons'.

You are correct in using the word "carried"

Yes. The pigeon carried the message. "bring" does not necessarily mean "carry".

aren't the same?