My other thought was a ram lamb, and then either sending him off for the table or selling him once he had done his duty!
I've never killed an "entire" ram lamb for the table, but it's certainly a no-no with pigs, as the hormones taint the flavour of the meat. Getting a ram-lamb to serve your girls is certainly fine, as long as they aren't bigger than he his!
The other thing is that once the boy has done his work, he may well not be at prime slaughter weight anymore - added to that, it'll be mid-winter, and he will be putting on bone growth rather than meat. This means you might have to keep him until april time anyway, to get decent meat back on him.
If you've got the room, and the fences, might be better just to have a dedicated ram/rams, that you change every 2 years to keep the bloodlines healthy.