I am all for it! I think it would be such a wonderful experience for your family to raise animals that will produce your food. It is all very sweet. The one con is that they are messy and smelly, but very good fertilizers.
We are planning on raising chickens next year when we are in a living situation that will allow them. I haven't done the price break down, but we spend around $20 a month for local, free range, organic eggs. I am sure that it would take awhile to "break even" from the initial investment. However, I think that taking charge of your food and allowing your children the experience is more important than the finances.