A lot of people aren’t sure what live weight they need, or want to specify lamb by age instead. But, if you specify you want a six-month old lamb, you could wind up with a 90 lb lamb, or a 30 lb lamb. There are many variables that influence how fast a lamb grows- its mother’s age and milk quality and quantity, whether its’s a single, twin or triplet, whether it’s a ewe, wether or a ram, what it’s eating, its general health and immune function, and its own genetics for growth. So, it’s really important to learn to know what live weight you desire to most clearly communicate your needs and ensure you understand the price per pound you are paying.
Here is a general guide. We typically raise our locker lambs up to 85-95 lbs live weight. Once they are killed, bled, skinned and gutted, the resulting hanging weight typically ranges between 52-58% of the live weight. This generally means a 44-55 lb hanging-weight carcass. If the meat hangs in a cooler for a day or two, there will be some “shrink” or weight loss from water evaporation. Then, once the frame is cut up into primals or retail cuts by you or the butcher, there will be some weight loss from the removal of fat and bone.
The final yield is typically 75% of the hanging weight, so you bring home about 33-41 lbs of retail cuts. This results in a small chest cooler full of meat that can fit in an above-the-fridge style freezer.
Note that weight ranges are specified here, because there is always some variation in nature. Two 90 lb lambs may yield differently, varying by five pounds or more in hanging weight. Looking at, or even physically examining lambs doesn’t always predict which one will hang at a better weight. So much depends on the volume of food and water in the stomach, how heavy-boned the animal is, and what the pelt weighs. By law, animals that are processed by custom-exempt butchers or by the buyer must be sold live and by live weight. And they are usually weighed in advance of the day of slaughter. So, we can’t guarantee exactly what hanging or final cut weight will result, this is part of the process of buying direct from a farm, is that some natural variation is inherent in the process.
Sometimes folks want to purchase a smaller lamb to use for BBQ, where the whole frame is cooked or roasted. In this case, a 30-60 lb live weight lamb is often ideal, rendering about 10-25 lbs of meat for serving.
You may find other farmers who are selling larger lambs, sometimes much larger. It’s true that some breeds of sheep can get up to a 120 lb live weight frame size at the age of six months, especially if they are grain-fed. But research has found that some of these breeds have lower eating quality, the meat can be less tender. And often lambs that are in the 120-150 lb range are just over-fat, the producer has kept them in inventory too long. This means you are paying for pounds of fat that will just result in “trim” or waste. We find that for Katahdins raised on grass, the 90 lb live weight range is a very nice size, the lambs are still very lean and young, and the meat eating quality is extremely high.