The Impact of Laying Hen Hybrids and Cage Density on Keel Bone Damage

The aim of this study was to

examine the effect of cage density and hybrid

variety on keel bone damage in laying hens.

Methods: In this study, two different hybrids

(Hy-line Brown, HB; Isa Tinted, IT) were used

and 3 different cage densities low (750 cm2

/hen),

medium (535.71 cm2

/hen) and high (375 cm2

/hen)

were applied. The research started at the age of

20 weeks and continued until the chickens were

60 weeks old. In the research, 396 chickens (198

HB, 198 IT) and 54 cages were used. Laying hens

were grouped by weight prior to cage placement.

At the end of the experiment, the body weights

of the chickens were measured. Additionally,

a total of 54 randomly selected chickens (27

HB, 27 IT) were slaughtered to determine keel

bone damage. After euthanization, the skin

over the chest area was removed, and the chest

structure was examined. The keel bone of the

chicken, whose chest area was examined, was

removed and scored. The chest area was scored

as present or absent for hematoma. A score of

“0” was given if no deviation or other damage

was present in the chest area. A score of “1” was

assigned if there was deviation or other damage

(thickened) in the chest area. The keel bone

was scored as follows: “0” for no damage, “1”

for mild deviation, “2” for moderate deviation

or thickening, and “3” for severe deviation or

fracture. Results: According to the results of

the research, hematoma in the chest area was observed more at low cage density (P<0.001).

Additionally, as a result of scoring the chest

area and keel bone; it was determined that

the most damage was in HBs (P<0.001). Cage

density did not affect body weight. Moreover,

keel bone damage was found to be more severe

in Hy-line Brown hens compared to Isa Tinted

hens (P<0.001). Conclusion: In conclusion, keel

bone damage was observed more in low cage

density and Hy-line brown hybrids