I am so confused with all the different things I have read so hoping someone can give me a clear answer. When do ducklings need grit? I have 3 ducklings 15-16 days old. They are still in the brooder on crumbs but looking at slowly introducing the grower pellets at 3-4 weeks old. Do they need grit to help them digest this? I will be putting the outside when the weather warms (we are in the UK) and I'm confident they will be ok without heat, so will they still need the grit when outside? What type of grit do I need? I read oyster shell has too much calcium for ducklings? Where do I buy it from? Thanks!