Biosecurity and Backyard Chickens

Chicks and Salmonella update

Sorry it’s been a while. We had a contaminated pipette shedding Salmonella into our samples, so we were delayed while we switched out pipettes, cleaned everything, implemented more stringent controls, and re-ran all our positive samples (we almost always collect more sample than we need and have the extra frozen).So here we are, in the third week of July, with nearly all the summer’s samples collected, and having run 177 samples since March 2020, while more than 90 samples remain in our freezers waiting to be run.

We have 16 PCR-confirmed positives out of 177 samples, for an all-time total of 9.0% of chicks positive for Salmonella. Of these, 7/89 come from NPIP-certified hatcheries, while 9/59 come from non-NPIP certified hatcheries. Another 29 samples came from individuals, with unknown sourcing.

So what does this mean?

• Almost 10% of all chick shipments are positive for Salmonella. This isn’t terrible, but it’s not great.
• The numbers for just this year’s samples are worse, with 15.5% of samples positive for Salmonella. This may be due to study design vs an increase in Salmonella-positive chicks.
• Chicks from non-NPIP hatcheries are roughly 2x as likely to contain Salmonella.
• NPIP certification does not appear to be entirely solving the problem. This may be in part because ag stores don’t always use the same hatchery year to year; if they re-use equipment from a hatch/shipment with Salmonella, there is a risk of passing it on to the new chicks. I’ve reached out to NPIP representatives to get a better idea of what the expected rate of Salmonella would be in NPIP-certified flocks, but no response yet.
• Store setup matters; leaving chicks in open pens is a greater risk to both the customers and the chicks. It’s better to leave chicks inaccessible to customers. Cleaning between shipments is also vital.

What can you do about this?

• Assume your chicks could have Salmonella
• Don’t kiss your chicks or hold them near your face. Chicks are messy creatures and may have fecal material on their feathers. Feces can be extremely Salmonella-rich (besides being gross)
• Supervise kids around chicks. It’s ok to pet them, but kids should wash their hands afterwards
• Wash your hands after cleaning chick pens or waterers and don’t clean out your chick equipment in the kitchen sink (bathtub is a better choice)

The last couple of weeks have been exciting for chicken & chick sampling results. Keep in mind that “exciting” for scientists is roughly the same as “interesting times,” in this case meaning we have found a lot of Salmonella recently.

ADULT BIRDS: We have found Salmonella in an additional flock of chickens, bring our adult bird totals up to 4/403 birds positive, and 3/31 flock positive (see chart below).

What does this mean for Vermont BYC owners?

• The bad news: Salmonella is 3x more common in Vermont flocks of chickens (10%; 3/31 flocks) than it is in western WA (3%; 1/34 flocks) or in the greater Boston area (1.9%; 1/53 flocks). Possible reasons for this difference includes a higher number of rural flocks in our study than in the WA and Boston studies (the Boston study was entirely urban). Wild birds, rodents, and mammals can all have Salmonella, and they can pass it on to backyard chickens, and our Salmonella-positive flocks have all been from rural farms/homes.
• The good news: looking at by-bird rates, Salmonella is extremely rare in chickens in Vermont, with fewer than 1% of chickens testing positive
• Other good news: In the flocks we tested, only one or two of the birds in each flock had Salmonella at the time we tested. This means that you do not have to cull your whole flock if one has/gets Salmonella

CHICKS: We have found our first positive samples from chicks purchased from flocks participating in NPIP. No system is perfect, but this is a bit concerning nonetheless.

What does this mean for Vermonters buying baby chicks?

• More than half our samples have come from NPIP-certified hatcheries, which are expected to be Salmonella-free
• 10/69 samples not from NPIP-certified hatcheries were positive (15%).
• 4/81 samples from sellers purchasing from NPIP-certified hatcheries were positive (5%)
• Overall, more than 7% of the chick pens/shipments we’ve sampled contain Salmonella, indicating that baby chicks often carry Salmonella
• Takeaway: Buying from an NPIP-certified hatchery or a store that buys from an NPIP-certified hatchery is the best way to reduce your risk of catching Salmonella from baby poultry, but you should still be careful about kissing or cuddling your baby chicks as no system is 100% sure.

Salmonella in baby chicks:

As of 05/11/21, we have tested 152 lots of baby poultry from agricultural supply stores, hatcheries, and individuals. We found Salmonella in one lot of turkey chicks last year and nine shipments of chicks this year (6.6% of shipments)

What does this mean?

• More than half our samples have come from NPIP-certified hatcheries, which are expected to be Salmonella-free
• Of the 56 samples not from NPIP-certified hatcheries, 8 were positive (14%).
• Two samples out of 79 (2.5%) from from NPIP-certified hatcheries were positive

Takeaway: Buying from an NPIP-certified hatchery or a store that buys from an NPIP-certified hatchery is the best way to reduce your risk of catching Salmonella from baby poultry

Salmonella and Campylobacter in adult chickens:

No new results

Salmonella in Adult Chickens:

As of 3/30/21, we have tested 30 flocks of chickens and found Salmonella enterica in 2 flocks (6.67%). The total number of birds tested was 393 birds (0.5% prevalence)

What does this mean?

• This is a higher flock positivity rate than other studies of backyard chickens have seen. A study in Boston found Salmonella in 1/53 (1.9%) of the flocks they sampled (McDonagh et al., 2018). A study of backyard chickens in western WA state found Salmonella in 1/34 (3%) of flocks tested.
• However, Salmonella is still rare in chickens in Vermont
• In the flocks we tested, only one of the birds in each flock had Salmonella at the time we tested. This means that you do not have to cull your whole flock if one has/gets Salmonella
• We have also found that the positive chickens have always cleared Salmonella by the time we get back to the farm to re-test (typically 2 weeks later)

Salmonella in baby chicks:

As of 04/09/21, we have tested 143 lots of baby poultry from agricultural supply stores, hatcheries, and individuals. We found Salmonella in one lot of turkey chicks last year and three shipments of chicks this year (2.8% of shipments

What does this mean?

• More than half our samples have come from NPIP-certified hatcheries, which are expected to be Salmonella-free
• Of the 52 samples not from NPIP-certified hatcheries, 4 were positive (7.7%).
• None of the samples from NPIP-certified hatcheries were positive
• Takeaway: Buying from an NPIP-certified hatchery or a store that buys from an NPIP-certified hatchery is the best way to reduce your risk of catching Salmonella from baby poultry

Campylobacter in backyard chickens

This year, we have begun to look for Campylobacter spp. in adult chickens. Unlike Salmonella, chicks don’t get Campylobacter through the egg. Instead, they typically get it from other birds with the infection. Adult birds are the most likely to carry Campylobacter spp. As of 4/9/21, we’ve tested 15 samples of bedding and found Campylobacter in 1 sample (6.7%).

What does this mean?

• This is extremely preliminary data, and the percent positive rate will change. Keep an eye on this page for updates. If you would like your birds tested, contact us to participate in our studies.
• Campylobacter is extremely contagious for chickens. Once one bird has it, all of the birds will get it.
• Campylobacter lives in the intestines of chickens. It doesn’t grow in the presence of oxygen, so chicken poop/infected meat is going to be the primary source of human infection by Campylobacter.
• However, Campylobacter grows to up to 10 billion cells/gram in chicken intestines (infectious dose: 500-10,000 bacteria), so a little bit of fecal matter can be enough to get you sick. Good hygiene is key here (handwashing after handling birds and eggs).