You can add it now but if the ground is still frozen you may lose a lot of nutrients to spring run-off. Better to compost it in large piles and add it later when the soil is easier to work and drier. Alpaca manure is easy to work with. You can use a lot - a 4" layer wouldn't be too much. As with any manure, you want it to be well composted or in the ground 90 days or more before harvest, especially with root crops or leafy greens, so composting it now will give you a head start. It will do wonders for your soil.

Alpaca, Llama, Vicuna manure is about similar in composition as sheep or goat and like all animal manures can be one of the additions to soil, when combined with vegetative waste. Just like when making a compost pile you should be adding 3 parts vegetative waste to your soil for every 1 part of animal manure to get the most out of that manure.
Whether you can add anything to your soil now depends. Is your soil workable now? if it is too wet to work, as mine is, don't. If is is snow covered, as mine is this morning, don't. Simply spreading the manure around and letting it lay on top of your soil is a large waste of valuable nutrients because those nutrients will simply evaporate into the air. Any animal manure spread over soil should be worked in as soon as possible afterwards to get as much of the nutrients the manure contains into the soil.

Did know of someone on another site that has used Alpaca Manure for years, even had red worms in it.
She lived in S.California.