I have access to straw bales that got wet in a storm and are now somewhat moldy. If I put these in my chicken yard for the girls to paly in will that harm them? I have 34 hens and they'd love sscratching tin them but will it hurt them? Their yard is 40'x120'. We have acreage but they can't free range bc of my labs and coyotes. that's why I gave them such a big area.