I've been using puppy pads for the bottom of the brooder. It's been great and there really hasn't been any smell (unlike the last time I had 3 wk old chicks in the house with shavings). The chicks range in age between 3 days and 1 week old and now they are starting to scratch. For those of you using puppy pads, how long do you use them? When, if ever, do you switch to shavings?