You could try, but the texture will be very different. Whole flaxseeds don't have the same ability to bind liquid as chia seeds do. That's why we blend them into flax meal. That way they can hold much more liquid (milk in our case) which results in a thicker, more pudding-like texture. Hence why I would recommend using ground flaxseeds. Another advantage is that ground flaxseeds are easier for the body to break down.