As we discovered quite early on in our poultry keeping career, adult birds LOVE chick crumbs and it can be a devil of a job to stop them eating them. They would not necessarily do them any harm but they are more expensive than the layers pellets plus if the adult birds gobble them all up, the chicks, ducklings etc then go hungry as they cannot eat the layers pellets (until bigger). We therefore have to get inventive. This is an upside down bread basket we believe that was here when we moved. We have added a couple of short legs and it works because the ducklings, poults and chicks can crawl underneath but the adult birds cannot – well, some of the smaller chickens do but the greedy turkeys and geese definitely cannot. As the young birds grow, they will eventually get too big to fit but by that stage they can progress to the layers pellets anyway!!
There is a body of thought that advises against given younger birds layers pellets too early (before about 18 weeks) as the feed contains higher levels of calcium than is needed for birds NOT yet laying eggs. Too much calcium can damage the kidneys. You can feed growers pellets in-between crumbs and layers to help counteract this but in our free range set up, this would be virtually impossible to achieve without separate pens (and therefore NOT free ranging!) Our theory is that as our birds free range they may not eat as many layers pellets as if they were contained, thus getting less calcium in their systems anyway. Also, vitamin D3 is essential for the proper absorption of calcium and because our birds free range and get plenty of sunshine, this MAY help the calcium NOT to build up!!
We don’t feel we lose too many birds for unknown reasons that could be attributed to kidney failure but the honest answer is we don’t know. Most of our birds live for several years so we can only assume that the extra calcium is not a widespread issue!!