It does cost FAR less -- in the long run -- to raise well-bred, healthy animals. That is why we all say "start up costs" can be hard, because we buy from healthy flocks., vice culls.
Many are happy to cover feed costs, have "own use" product, and maybe a little extra. Others have a farm business that is successful but not new, only hard earned & developed over time.
I raise chickens, sell eggs, sell a few chicks and/or young pullets. Always have eggs to eat, chickens to butcher (especially extra roos that are hatched, grown out) and this sure reduces grocery buying. So, my chickens support themselves.
My dairy goats are milked. I use the milk, make cheeses, soaps, and have sold a little milk to animal rehab groups. The kids that come each year for freshening are generally 100% sold. That pays for a majority of their hay/feed. Excess milk, cheese whey, helps feed chickens & pigs -- if I am currently raising a couple for freezer camp. I sell goat milk soap at a few annual festivals, a couple beauty shops, etc.
And I raise a garden, can & freeze, sell some excess, give some away, use some to feed to all the animals. In fact, raising some excess of certain produce JUST for animals.
All of these things require physical labor and can be sustainable but, you will not get rich! It sounds as if you may want to consider & research flocks of chickens, ducks, turkeys. They all have their own requirements for feed, fencing, shelter, care but are smaller and less taxing physically than sheep & goats weighing 1-300 pounds. Have you ever raised animals? Do you have any now? If not, there's some major learning before you buy, otherwise you just threw your $$ away.
Another thing I read is that you are involved in raising your grandkids. So can the parents help out both financially and physically? You may need to tap into that resource to help make your farm sustainable for everyone. As others have said, you also need to have a plan & goals, which include where/how you can market your "product". Everyone replying has, or has had, so very many issues in their lives to get to where they are now and offer great input for you to consider. This will not be an overnight successful input to your bank account -- unless you sell the farm. Most of us work at "maintain & improve" with a frugal lifestyle....some are still working before/after retirement.
I hope we have given you some things to consider that may work. Never a day we won't be here to answer questions & listen to your thoughts, offer suggestions and sound advice based on years of experience -- good and bad. LOL
As long as the animals are getting proper care and have proper shelter/fencing etc. However, I do not agree with breeding a doe 2x a year, every year, in an effort to bring in extra money. 
There may be exceptions, but this is very taxing to the animal.
