It is difficult to get the mice to take the pill, they're probably smell a rat if you crushed it and put it in bait. Maybe you'd be better off buying extra extra small condoms and rushing around fitting them to all the male mice.
There are a whole host of substances that can act as contraceptives in rats. Rats are mammals like us after all and their physiology is very similar to our own.
As has been said above, the problem is administering the drug.
Incidentally, don't forget that physical sterilisation is also possible. If you can catch them , take them down to your local vet who'll do the job for you but it will cost you a few bob.
A good biology lab technician should also have no difficulties with this too as long as the lab is reasonably well equipped.