Page 11 - National Poultry Newspaper

High UV radiation and hot temps affect hens’ range use in summer
Range use decreased when the ambient temper- ature, UVA/B and PAR increased, indicating that hens are sensitive to spe- cific wavelengths of sun- light and they avoid in- tense radiation that may be visually aversive or damaging.
Exp-2
* from P10
sunlight and shade from previous sunny days were marked and the number of hens counted in the ‘cloud’ and ‘cloud-shade’ respec- tively.
ture and relative humid- ity sensors recorded these ambient parameters.
the midday period.
This suggests that ar-
An onsite weather sta- tion was set up on each farm to record the irradi- ance or intensity of dif- ferent sunlight spectrums using specific sensors, in- cluding UVA/B radiation 288-432nm, photosyn- thetically active radiation 400-700nm – this is vis- ible light – and total solar radiation 285-3000nm.
As expected, in the ‘sun’, range use by hens was de- creased during the midday period, which then gradu- ally increased over time in the late afternoon to evening, with the opposite pattern observed in the ‘sun-shade’ – see Figure 2.
tificial structures might not be sufficient to attract hens outside during sun- light periods across sum- mer.
Infrared radiation 700- 3000nm was later extract- ed from TSR.
The distribution of hens on the range was also in- fluenced by months indi- cating seasonal effects on hen ranging – see Figure 4.
Shelters on the range should have the highest sunlight filtering capacity to protect hens from the damaging effects of sun- light radiation.
Figure 4: Hen range use in sunny and cloudy conditions across months on a commercial farm in Western Australia.
Figure 5: Sunlight-filtering cloth shelter preferences by hens across the day in two flocks (a) and (b) of a commercial farm in Queensland.
In addition, air tempera-
Across the summer, hens’ shelter use during the day was video re- corded, with sunlight and weather data recorded through an onsite weather station.
Finally, we would like to acknowledge Australian Eggs for funding this re- search and we are thankful to the generous support of all the commercial farms involved in these studies.
Md Sohel Rama DVM MS PhD research fellow at the University of New England.
The ambient temperature was the greatest predic- tor of hens’ shelter usage overall, where fewer hens were underneath during
• Commercial free range laying hens’ preferences for shelters with different sunlight filtering percent- ages – doi.org/10.3390/ ani12030344
In cloudy conditions, there was a similar pattern of range use across most of the time points – see Figure 3.
The outdoor range of two different sheds on a com- mercial farm in Queens- land was enriched by placing UV-filtering cloth shelters of different densi- ties – 90 percent, 70 per- cent and 50 percent UV- block but visually blocked all sunlight spectra – with three replications each.
In a nutshell, hens’ range use is impacted by bright sunlight with high UV ra- diation and hot tempera- tures when sunlight is at its most intense.
Hens’ shelter prefer- ences were determined by counting the number of hens underneath the shelter from image snap- shots taken at 30-minute intervals during pop-hole opening to slightly before sunset across 14-17 days.
For more information, contact Dr Dana Campbell at dana.campbell@csiro. au and Md Sohel Rana at ranasoheldvm06@gmail. com
Across most time points throughout the day, hens preferred shelters that fil- tered the most sunlight – see Figure 5.
• Relationship between sunlight and range use of commercial free- range hens in Australia – doi.org/10.1371/journal. pone.0268854
Full publication of the two studies are also avail- able online:
Md Sohel Rana
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National Poultry Newspaper, July 2022 – Page 11