Q: What is the deep litter method of coop bedding management, and how does it work?
A: The traditional way to manage bedding in the coop is to put a light layer of bedding down--for bedding recommendations, see the related questions below--and then change out the bedding once a day or once every few days. (How often you'll have to clean depends on how many chickens you're keeping in how much space.) It's pretty straightforward; you more or less clean it like a cat litter box.
By contrast, in the deep litter method, you start with five or six inches of organic, compostable bedding such as pine shavings, and then simply add new bedding on top to keep the litter deep. As the litter breaks down, it basically composts inside the coop. If you toss down some treats, your chickens stir the compost (aerating it, which is necessary for proper management). Believe it or not, it's odorless. In fact if there is an odor, it shows either you have not been adding enough new bedding, or you don't have enough ventilation (or both) so step it up! You will probably have to rake the litter in the corners and under roosts yourself to make sure everything is nicely stirred. Chicken manure has a lot of moisture in it, so you need to make sure your built up litter doesn't become too wet. Eventually the litter level builds up to 12 or more inches, because you only change the bedding every six months or a year with the deep litter method. Leave a little when you change the bedding so that those good bacteria already have a good headstart with the new layer.
Why use the deep litter method?
Well, there are quite a few benefits. First of all, the beneficial bacteria that build up in composting litter help keep any harmful microbes at bay . Secondly, composting litter produces heat; this can help keep your chickens more comfortable in the winter, if you live in a cold winter area. Thirdly--and you've probably thought of this one already--you'll be cleaning less frequently. Of course there will certainly be more to clean out when it comes time, but there is more flexibility with this chore, since it's not normally a problem to move it a week or two forward or back to coincide with mild weather. Another benefit is that when you remove the deep litter, you may already have partially matured compost on hand to spread in your garden (do be sure to compost it a bit further outside in a compost pile to make sure that top layer doesn't burn your plants.)
And what's really kind of an amazing benefit is that chickens raised on deep litter have increased access to Vitamin B-12, which they get as they pick through the litter. Crazy? Maybe a little. But the weird fact is that chicks raised on litter grow better and larger, and tend to be healthier than those raised on wire or even paper (which we never recommend anyway, as it can lead to splayed leg). And another amazing benefit is that deep litter has anticoccidial properties.
When may the deep litter method not be appropriate? Well, firstly, if you've experienced illness or parasites in your flock, you'll want to clean everything, EVERYTHING, out and sanitize. Don't keep your chickens on litter that may be harboring anything unhealthy. Secondly, some extreme environments may make managing deep litter more challenging. For instance, if you live in a very dry environment (and/or if your chickens have a very large coop), it may be difficult to maintain the proper amount of moisture in the bedding so the litter breaks down. If you live in a super-humid place (and/or if your chickens are too crowded in the coop), it will probably be difficult to keep the litter dry enough. If it's very cold where you live, it may be difficult to get the composting properly started, because the cold will slow down the process!
Although there are some instances where the deep litter method may not work efficiently, it's wonderful when managed properly.