I only know tiels not IRNs and at 5 it's time to call the vet with a tiel. Tiel hens can and do sometimes seize from low calcium. It's not a pretty sight. But mine all came to me over the years unvetted and were throwaways so I'm dealing with those not having had any medical care before me. The prior owners just let them lay as they did and had a whatever happens to them happens mindset. A hypocalcemic hen tiel can have a 'silent' seizure where they just freeze for an hour or two or they can have a rigid thrash seizure for a minute or so.
I do use a supplement under the direct supervision of the AV. Please call your AV over your girl. I don't know IRNs but a laying hen is a laying hen. I'd hate to see your girl seize up or bind from low calcium. Sodium is also important for preventing binding. Thanks for being you! These ladies are up against so much in captivity. My AV and I do lupron after 6 and I have to get her in within a few hours after the sixth egg is laid as my vet likes to give the lupron shot before another egg has had a chance to start to form. But I'm not playing vet just sharing my jouney with tiel hens. Sometimes I have no idea how I got into this years ago but if I don't do it few others will.... My best to your girl.
The Heavens Created Birds, then man created cages, shame on man.