My leghorns are now 5 weeks of age. A week ago I began carefully reducing the amount of medicated starter in their diet, and adding meat bird finisher (which is coccidiostat-free). The reason for moving to meat bird finisher is that it's sufficiently high in protein for chicks to grow.
Now these birds have been reared so far in the brooder (3 weeks) then in a small aviary with a concrete floor (2 weeks). When I first put the chicks in the aviary, I covered the floor with a half-inch of crusher dust and then a layer of oaten chaff for litter, and this was sprinkled lightly with water with a small amount of adult hen droppings to introduce a coccidiosis challenge (as well as any beneficial bugs that may be in the hens' digestive system).
In those 2 weeks we copped a heap of rain, and the floor of the aviary ended up quite wet due to a leaky roof. Frankly it's not an ideal situation for young birds, but despite what must have been a considerable cocci challenge, none of the chicks became ill. I put this down to a low number of birds (I sold some, so was down to 7), the fresh litter with its reasonably controlled cocci load, and the fact that the chicks had also encountered cocci oocysts in small numbers in the brooder (via a tiny bit of adult hen droppings introduced into their water, along with some probiotics in a diluted Yakult drink...).
Yesterday I reduced the medicated starter to zero, and moved them to the tractor outside, on ground that has had chickens in the past 6 months but has also got a dense mat of new spring grass. I'll remain watchful even now, but I don't expect too many coccidiosis issues now, as these birds have proved themselves capable of dealing with wet ground and a seven day withdrawal of medication.
So to put this simply: I have five-week old chicks running on damp ground without medication. It's too early to be triumphant, but I'm hopeful that I can eventually be raising chicks without coccidiostats. Earlier and careful weaning will let me find out the limits on medication removal without unnecessarily harming chicks!
Above: the current diet consists of either commercial meat finisher or (as in the picture) the sprout mix including meat meal to raise protein content. Meat meal has its share of problems including too high phosphorus against calcium (if given to layers it can cause soft shelled eggs and other issues), and of course it's an inferior byproduct. However it's still commonly used in commercial chicken feeds, so it's difficult to avoid anyway, and often the alternatives are synthetic (such as artificial methionine). I've increased protein in other ways as well, such as higher lucerne chaff content (soaked chaff is best), and molasses-soaked field peas. The chicks are enjoying the sprout mix!
I'll keep an eye on the chicks and if they look at all peaky, or go off food (the first sign of cocci) I'll move the tractor daily; at present, however, I'm planning to only move it when the grass diminishes (probably a week or so).
Of course, it may be that my system will suit a completely medication-free approach; or it may be that I always need to use small amounts of medicated starter but can continually wean early with careful management. Or it may be that as time goes on, the coccidiosis oocyst build-up in my tractor area's soil becomes too great for young chicks... However there's a theory that cocciodiosis oocysts have predators of their own; if that's the case, I would expect that soil numbers will stabilise.
Lastly I guess I could try other feed inclusions like fine grade dolomite (claimed to help grind parasites like worm and coccidiosis oocysts up in the gizzard), apple cider vinegar (claimed to acidify the gut against various parasites) and garlic. However for now I'm just looking at nutrition, fresh feed and litter management.
The experiment continues...
