for chaffs it is roughly 2-3 generous stubbs scoops =1kg. Best to weigh it though as it depends how compacted or fluffed up it is.... or if the bag contains 20kg... divide the volume by 20!
That post was unnecessary K_T - i do not have weighing scales in the feed barn in the livery yard i'm at though will be investing in some. That is not the question I asked now was it.
Thank you to those who DID try and help constructively, I was looking for a guestimate so that I can plan how much feed to buy to take back up to uni - it is difficult finding a feed merchant up there.
Have now gathered that 1kg readigrass will be approx 4 rounded scoops - therefore split that into 2 big rounded scoops a day if split into morning and evening feed woo my brain is working again! lol