That looks like the right kind of chain for the lengths between the bars. Purchasing by the roll is lots cheaper than by the link!! You could take one of your links off the spreader, take it with you to compare sizing before purchase.
MillCreek was the first small spreader company to use “real” spreader chain, spreader bars, so it was easy to find replacement parts. Those parts held up to real loads of bedding for emptying the spreader. Not like those old mini spreaders with toy size bars and chains that broke so easily with any load on them.
You will need special links for holding the bars to the chains. The link has a kind of a tab that sticks inward to fasten bar to, so you need a right and a left link for each bar.
Husband makes the bars for our spreader, fastens those special links on them, keeps a supply for when something breaks. Certainly costs less than purchasing the bars. He gets parts from the farm store. He uses a come-along device to tighten the chains for fastening them back together after I break links or a bar needs replacing.
He replaces any “iffy” links, badly worn bars, when he is already putting other parts on. Links with thin bars or the worn rolled end to hook them together, are going to break soon. Easier to fix all at one time, than having to repair twice in short times. OR HAVING to fork out the spreader to get down to the chain and bars after it breaks on you!
I try to dump the spreader daily, which lengthens the life of bars and chain links incredibly. Urine just eats metal it sits on.
Good luck with your new-to-you spreader. I like MillCreek spreaders.