That isn't what my Sweetgrass look like.
http://www.porterturkeys.com/sweetgrass.htm
https://www.backyardchickens.com/t/966414/a-century-of-turkey-talk-2000-2100/9450#post_17481714
What you have seen are not Royal Palms. Pure Royal Palms do not have any color other than black and white. There are far too many turkeys being sold as something they are not because the sellers and buyers do not know any better.
http://www.porterturkeys.com/royalpalm.htm
I don't know what you have but the one that you think is a Royal Palm is definitely not a Royal Palm. Royal Palms only have black and white and do not have any brown feathers.
http://www.porterturkeys.com/royalpalm.htm