I have no idea, honestly. Never had an issue with it with any of my other birds, and I honestly am happy to downsize by 3 birds and not troubleshoot. I know that sounds bad but.... That's how I feel about it. I've tried several breeds of birds and they're one of the ones I haven't been big on. I like my dorkings and dominiques. My cornish are kind of aggressive and crazy but maneagable. So those 3 stay. And our white orpingtons are fine. I'm over chicken breed experimenting, we'll keep and breed what we have and upgrade when we can to better quality of the 3 we like!