Writing in an exclusive article for Poultry Health Today, Mr Barbosa said that numerous studies from around the world have demonstrated that when the time between hatch and placement is delayed, bird performance suffers. [1]

Taylor Barbosa, DVM, MS, PhD, ACPV

Conversely, studies show performance is enhanced by early placement that gives chicks access to feed and water during this delicate stage of their life cycle.

Just one example of the research comes from investigators in Brazil and the US who compared broiler chicks placed immediately with those placed 24 hours after hatch.

Chicks with delayed access to feed and water had a 50% reduction in yolk-sac contents. Their weight was 13.1% less at placement compared to chicks placed immediately, and their weight was not recovered by marketing at 7 weeks of age. [2]

In another study, investigators provided chicks with feed and water either immediately after hatch, or 16, 32 or 48 hours later.[3] The adverse effects of delaying feed and water for 48 hours were still evident when the birds were marketed at 42 days of age.

Broiler chicks, they explained, cannot fully compensate for growth retardation caused by long-term food and water deprivation. Providing neonatal chicks with appropriate nutrients as soon as possible “is essential for development of supplying organs such as the gastrointestinal tract.”

Placement of chicks on the farm can be delayed for several reasons. Hatchery tasks such as counting and sexing must be performed. Another task that can considerably delay placement is subcutaneous vaccination.

Since birds have to be handled individually, it can take anywhere from about 8 to as long as 20 hours, depending on the size of the hatchery’s labour force.

Expediting placement

We have found that one way to expedite placement is by replacing subcutaneous with in ovo vaccination wherever possible. It can considerably reduce the time it takes to get chicks from the hatchery to the farm. In most cases, vaccines that can’t be given in ovo can be sprayed on at the hatchery, which takes only minutes to accomplish.

In ovo vaccination has added advantages for the hatchery. In markets where labor is expensive, it can reduce labor costs.

Another advantage of in ovo vaccination is disease protection, depending on the equipment used. In two field studies conducted at commercial hatcheries in Brazil, investigators compared the dual-needle Inovoject® system with subcutaneous administration of a live, wild-type Marek’s vaccine.

In the first trial, 95% of the in ovo group was positive for herpesvirus of turkey — an indicator of vaccine take — compared to only 66% of the subcutaneous group at 21 days of age. In the second study, vaccine coverage was 10.63% better with in ovo compared to subcutaneous vaccination. [4]

In a separate study published in Poultry Science, the dual-needle in ovo system used at one hatchery correctly vaccinated more than 94% of eggs compared to only 61% with a single-needle system.[5] At a second hatchery, the dual-needle system correctly vaccinated 91% of eggs compared to 72% with a single-needle system.[6]

In ovo vaccination can help improve bird performance by enabling chicks to be placed sooner rather than later and is a strategy well worth considering. The benefits of early placement can be enhanced with disease protection afforded by the dual-needle in ovo vaccine system and can translate into better profits for producers.

[1] Vieira SL, et al. Effects of delayed placement and used litter on broiler yields. J Appl Poult Res. 1999;8:75-81.
[2] Ibid.
[3] Abed F, et al. Do broiler chicks possess enough growth potential to compensate long-term feed and water deprivation during the neonatal period? S Afr J Anim Sci. 2011;41(1):33-39.
[4] Data on file, Study Report No. 3Z10R-04-11-530, Zoetis Inc.
[5] Williams CJ, et al. Field evaluation of the accuracy of vaccine deposition by two different commercially available in ovo injection systems. Poult Sci. 2011;90:223-226.
[6] Ibid.