there's two different sorts-garden lime which raises pH and not so potentially harmful to stock but isn't as good at killing nasties-or builders (hydrated) lime which is more effective at killing nasties but not so good for your animals and plants.
I've used both-I used garden lime on my grass pens and I've used builders lime on earth pens, dug it in well and left if for a couple of months. If you only have the three banties and are moving them regularly, you'll not need to lime often.
If you are moving them around your lawn, garden lime is what you need-builders lime is not nice stuff.
[/size][size=78%]For garden lime I usually keep them off for a few days, until its well rained in. [/size]