Score by hand — the fleece is lying to you
Alpacas carry their disguise with them. A senior in full fleece can look rounded and well-covered while her ribs, spine and hip bones stand out sharply to a hand pushed through the wool. Score her properly and often: feel along the backbone behind the shoulders, across the ribs and over the pelvis, comparing what your fingers find with what your eyes reported. Do the same with her herdmates so you have an honest yardstick, and write the scores down — a slow slide from one month to the next is exactly the pattern memory misses.
Watch her eat before you change her feed
How she eats tells you where the problem lives. An alpaca who approaches feed keenly, then chews slowly, drops half-chewed forage or works one side of her jaw is telling you about her teeth: alpacas' teeth grow and wear throughout life, and an old animal's mouth can develop points, uneven wear or loose teeth that make every mouthful work. Competition is the other silent thief — in a herd feeding from shared hay, the slowest elder is simply out-shouldered. Before adding anything to her diet, separate the two causes: watch a full feed, from first approach to last swallow.
Feeding her away from the herd's hurry
Give her her own feeding space, even if it is only a penned corner of the shelter at feed times, where she can take an hour over what a youngster finishes in minutes. Offer her your best hay — soft, leafy, dust-free — rather than the coarse stemmy bale, because an old gut extracts less from poor forage and old teeth manage it worst. A senior-appropriate concentrate or soaked feed, introduced gradually, can add what hay no longer supplies, but change one thing at a time and re-score weekly so you know what is working. Clean water she can reach without being jostled is part of feeding, not an afterthought.
Read her against the herd, not against hope
The herd is your control group. If every alpaca is thinner after a hard spell, suspect the forage or the season; if she alone is sliding while her companions hold their scores, the problem is hers — her teeth, her health or her place at the feed. Sudden loss over a fortnight is a different signal from a slow seasonal drift and should shorten every timeline in this article. Weigh her if you have scales, or at least condition-score on the same day each month, so the comparison is between measurements rather than between memories of how she looked.
When feeding is not the whole answer
Continued loss despite good feed eaten in peace has a medical list behind it — dental disease, parasites, and age-related organ or gut problems among them — and it belongs to your vet, promptly, not to another month of trial and error. Go sooner if she stops eating, isolates herself from the herd, lies down more than usual or her droppings change. Arrive with evidence: the dated condition scores, what you changed in her feed and when, and how she responded are precisely what her KinsLe Pet Passport keeps together in one packet for vet visits like this one.