My practice is NOT to provide blocks of cuttlefish in cages or flights - it just takes canaries too long to get enough for themselves by pecking at it - budgies and hookbills are different - they can whittle a block to powder in five minutes. I prefer to take a small vegetable paring knife - I use one with a serrated edge - and cut thin 'shavings' from the cuttlebone - about 2-3mm in thickness. I lay these chalky wafers on the cage floor next to the egg food when pairs are getting ready to lay eggs. Canary hens will drop everything they are doing as soon as they see that cuttlebone wafer and will eat several beak-fulls on the night before they lay each egg.
The cuttlebone is dissolved by the digestive acids of the bird's proventriculus and is then ground to a watery slurry by the grinding action of the grit-studded gizzard. It then passes into the rest of the digestive system where the calcium and magnesium salts are absorbed into the bloodstream. When the hen is about to lay an egg, calcium is secreted from the bloodstream into the oviduct where it is laid down as a protective shell around the watery egg. I continue to provide cuttlebone-shavings during incubation, because logically the hen may need to replenish her calcium supplies in bone and blood after producing a clutch of eggs.
Limestone grit is another important source of calcium for canaries - supplied as small granules from 2mm to 3 mm in size. Limestone is soluble in weak acids and when eaten by the birds it lodges in the gizzard where it is washed by digestive acids and slowly ground and dissolved. So limestone grit serves as a kind of calcium buffer for canaries and other finches - a long-lasting source of calcium which is percolating into the bird's blood very slowly, as required. Using this regimen of cuttlefish bone supplemented with limestone grit, seashell grit and other grits, which I inherited from my father's management of canaries, I have never had an egg-bound hen and I have never seen a soft-shelled egg.
When pairs are raising chicks I adapt the technique slightly by producing a finer 'cuttlebone powder' - by scraping the knife across the surface of the cuttlebone and allowing the powder - about half a teaspoonful - to fall into each batch of egg food. Chicks grow at a furious pace, and bones, feathers and blood need lots of calcium and magnesium - carbonates and phosphates.
I suspect that cases of chicks with splayed legs and 'slipped claw' may be related to lack of calcium.
Interestingly, cuttlebone powder has been used in Vietnamese and Chinese traditional medicine as a 'recalcitrant' for rickets, as an anti-haemmorragic and for gastro intestinal problems. The anti-haemmorragic use is very interesting - I assume they just grate the cuttlebone powder onto bleeding wounds as an aid to clotting - it also has antiseptic properties as well. if I ever have another case of a canary with capillary bleeding on its foot or leg I might try this - almost nothing else worked at the time.
 |
 UK
Contacts |
 Links |