How to show checked checkbox form update in Codeigniter 4

I have a problem to showing checked checkbox in form update,

my views:

<?php foreach($pertanyaan as $p) { ?>
<form action="<?= base_url('SAdmin/PertSurvei/edit/'.$p['id_pert']); ?>" method="post">
<div class="form-group row">
          <label class="col-sm-4 col-form-label">Animals</label>
          <div class="col-sm-8">
            <div class="form-check">
              <label class="form-check-label">
                <input type="checkbox" name="animals[]" alt="Checkbox" value="Chicken" class="form-check-input" <?php if (in_array("Chicken", $p)) echo "checked";?>>
                Chicken
              </label>
            </div>
            <div class="form-check">
              <label class="form-check-label">
                <input type="checkbox" name="animals[]" alt="Checkbox" value="Cow" class="form-check-input" <?php if (in_array("Cow", $p)) echo "checked";?>>
                Cow
              </label>
            </div>
            <div class="form-check">
              <label class="form-check-label">
                <input type="checkbox" name="animals[]" alt="Checkbox" value="Pig" class="form-check-input" <?php if (in_array("Pig", $p)) echo "checked";?>>
                Pig
              </label>
            </div>
          </div>
        </div>
</form>
<?php }?>

my controller:

public function edit($id_pert)
    {
        $data = array(
            'id_pert'       => $id_pert,
            'pertanyaan'    => $this->pertModel->detailPertanyaan($id_pert),
            'pertanyaan'    => $this->request->getVar('pertanyaan'),
            'id_unit'       => $this->request->getVar('id_unit'),
            'animals'      => implode(", ", ($this->request->getVar('animals'))),
            'id_kat'        => $this->request->getVar('id_kat')
        );
        $this->pertModel->editPertanyaan($data);
        return redirect()->to(base_url('SAdmin/pertSurvei'));
    }

im using modal bootstrap for form update. Does anyone know where the problem is? what should i do?