When to take kids from Mom to bottle feed.

[mistee]

I just started 3 kids on a bottle and they r 3 weeks old.. 2 will be leaving in 2 weeks to go to their new home so I wanted to start them on the bottle 4 them.. I was aalready seperating momma for a few hours a day so i could milk her so I just started offering a bottle.. the does took it instantly but the buck took a few tries.. i didnt push him just offered it once or twice and by day 3 he was sucking it down.