The board, at the time and place mentioned in the notice of the filing of the petition for exclusion of lands, or at the time or times to which the hearing of the petition may be adjourned, shall proceed to hear the petition, all evidence or proofs that are introduced by or on behalf of the petitioner or petitioners, and all objections to the petition that are presented in writing by any person showing cause why the change of boundaries should not be made, and all evidence and proofs that are introduced in support of such objections. Such evidence shall be taken down in shorthand, and a record made thereof and filed with the board.