The first thing to consider is that Lactated Ringer's solution contains sugar so if any impurities like bacteria finding their way into to the solution they are more likely to grow/survive. Normal Saline does not contain sugar so if one was use an IV solution where there was any question, the Lactated Ringers would be a riskier choice. Also keep in mind that Intravenous therapy is delivered straight into body bypassing the normal protective barriers of the body, even if using as subcutaneous fluids you are bypassing the bodies protective layers.
Even with the best supplies and care IV related infections (Sepsis) does occur; in fact "Sepsis occurs in 1% to 2% of all hospitalizations in the U.S."
So what Kind of shelf life does a bag of Lactated Ringer's have?
It varies widely by manufacture and packaging I find examples ranging from 18 months to 5 Years. There has been some discussion about use past expiration during times of difficulty but I don't find FDA approval.
If there is no posted expiration date, you should be able to contact the manufacturer with the lot number and get an expiration date. In any case I would recommend donating to shelter or rescue, if it is usable they WILL use, while you might use it. There are several rescues in your area, I would contact them each to ask specifically about donating IV solutions, as some may be more in need of the donation then other. I would not recommend donating by anonymous drop off.