I have zero experience with macaws, however my little lorikeet hen, Lilly, was an
awfully chronic infertile egg layer, and as you probably know this condition can lead to some very serious health issues if left unchecked. I was able to control her laying by providing her with a dummy egg that she could sit on to her heart's content - I'm not sure what part of the world you live in but the following link will give you an idea of what is available ...
DummyEggs sells 8 sizes of plastic broody bird eggs to Stop Egg Laying fast, safely, naturally. Non-toxic, fake bird eggs made in USA.
www.dummyeggs.com
From what I read on the interweb, macaws sit on their eggs for around 4 weeks until they hatch, and most hens of any species will lose interest in the eggs maybe a few days to a week beyond this, when they realise for themselves that the eggs are not viable and give up of their own accord. Once your hen has finished with this cycle you'll need to stop her accessing anything and everything that even vaguely resembles a nesting site and ensure she is only ever petted on the head and neck to avoid over-stimulation.
I have to say, however, that there are other complications from egg-laying other than the usual vitamin/mineral depletion in the body and egg-binding issues that are the most immediate concerns, so I would also recommend that you consult an avian specialist vet for advice, and have her thoroughly checked and blood tested, perhaps once this current cycle ends. One of the things that also cropped up with Lilly was a very fatty liver, because she desperately wanted to lay eggs and was eating A LOT of food in preparation for it, and when the energy from that food didn't go into egg production it went to her liver and was stored there as fat instead, and it caused her to have kidney issues too. So you may also need to overhaul your hen's diet to remove fruit or treats that are high in calories in order to try and prevent this, and I recommend you consult with your avian vet about this too. I mention all of this to you because I lost my precious little Lilly to a combination of all of these factors above, and I would hate to see anything like this happen to you.