Hi don't wean them yet, they are too young, I would be tempted to continue with 3 smaller feeds until they start on the creep and hay, are they on grass? They need to start eating hay or grass to get The tummy working properly, bloat is a build up,of gases, it's serious and if left the lamb will die, it's caused by too much concentrate in one go then.nothing, think feast and famine! They copy other sheep eating grass and hay, If that's not an option then sit with them and pick at the hay or grass to get them interested, I would cut to 2 feeds at 6 weeks assuming they have an intake of feed and grass, then to one feed at 9-10 weeks, then stop completely, they will yell and yell but will get over it.