Gypsy was born October 13th. The Holsteins were purchased on October 20th and 30th. So the youngest (the one with the most black on his body) is a month old. Gypsy is six weeks old, and Whitey (the one my grandson bought from me) is five weeks.
The three of them together are now consuming about two large coffee-cans of calf starter daily and eating quite a bit of hay. In an emergency, I could wean any of them and they would survive on starter and hay, but there's no need to do that.