bagaimana get data yang ada relasi tabel lain - api laravel

bang bagaimana get data yang ada relasi dengan tabel lain? di model sudah di buat relasinya seperti ini

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Province extends Model
{
	protected $guarded = [];
  	public $timestamps = false;

    // relasi kab
   public function regency()
     {

         return $this->hasMany('App\Regency');

     }

}

regency.php

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Regency extends Model
{
	protected $guarded = [];
  	public $timestamps = false;
//   	new
  	protected $table = 'regency';

  public function instance()
  {
  	return $this->hasMany('App\Instance');
  }

   public function result()
  {
  	return $this->hasMany('App\Result');
  }

  public function digitalrecord()
  {
      return $this->hasMany('App\Digitalrecord');
  }

//   relasi provinsi
 public function provinsi()
  {
  	return $this->belongsTo('App\Province','province_id');
  }

}

untuk controller seperti ini

    public function kab_index()
    {
        // return $regency->toArray();
         $data = \App\Regency::with('provinsi')->get();
         if(count($data) > 0){
            //mengecek apakah data kosong atau tidak
            $res['message'] = "Success!";
            $res['values'] = $data;
            return response($res);
        }
        else{
            $res['message'] = "Empty!";
            return response($res);
        }
    }
    public function kab_show($id)
    {
    $data = \App\Regency::with('provinsi')
            ->where('id',$id)->get();

    if(count($data) > 0){
        //mengecek apakah data kosong atau tidak
        $res['message'] = "Success!";
        $res['values'] = $data;
        return response($res);
    }
    else{
        $res['message'] = "Failed!";
        return response($res);
    }
    }

route nya

	Route::get('kab','Admin\RegencyController@kab_index');
	Route::get('kab/{id}','Admin\RegencyController@kab_show');

saya akses masih gagal (tidak muncul datanya) halaman kosong mohon pencerahannya bang