DES MOINES, Iowa (AP) — A California law approved by voters that promises to get breeding pigs out of narrow cages that prevent them from standing or turning will finally take effect Saturday, after years of delays and warnings that the rules could lead to price spikes and pork shortages.

But it will be six months before California grocery shoppers can be sure that pork chops they buy under the new law will be from a pig whose mother wasn’t confined in a so-called gestation crate.

That’s because while the U.S. Supreme Court upheld the law, the state recently agreed to allow pork slaughtered before July 1 to be sold in California markets and restaurants for the rest of the year. That decision gives farmers and grocery stores time to adjust. But it’s exasperating to supporters of the new rules that the effective implementation of the law would again be delayed — four years after voters approved it.