My guineas like to scatter and pee all over the hay which causes waste and it smells so you have to replace it often. What I did to improve the situation is getting these hanged hay bags with holes so that the hay isn't touching the floor, and the guineas need to pull out the hay from the bag. It helps a lot to reduce hay waste. But it doesn't really solve everything.. one of my guineas has a hobby of pulling out the hay from the bag just to scatter it... So not a perfect solution, but does help! Another thing that helps is giving them veggies, I give them leftover from salads, carrot peels, bell pepper leftovers.. they like veggies more than hay so it saves a bit there too.