I've had my boys a month and hate the thought of them being outside so been looking for an indoor cage and found one id like to get. Dimensions Lx 39" Wx 22" Hx 17". I would like to know what's best used inside the cage to have minimal smell? Currently I have woodshavings outside but it's so messy I want to change that once they come in. Any other advice for indoor piggies much appreciated, thanks x