Diary of a Poultry Farmer: What can shorten your eggs shelf-life

Friday December 02 2016

Collected eggs stacked and ready for storage. Dirt on eggs may imply contact with chicken manure, which is a vehicle for transmitting salmonella. FILE PHOTO | NATION MEDIA GROUP


“I need five trays of eggs,” Jackie, a regular customer told me the other day.

“I have some, but you have to wait until the weekend when I go to the farm,” I offered.

“That is fine, but there is something else. In the last package, a few eggs were spoilt. I need them fresh this time round, otherwise I will stop buying from you,” she muttered.

“What happened?” I pried, “Were they smelling or broken?”

“A few had a smell of sulphur,” she said. I offered her one tray for free so that I could not lose her.

For sure, this was the third customer in one week who had complained and I decided to do some investigations.


In fact, another client, Joash, wondered if at all this had to do with ‘egg fertility’.

You see, I rear Kienyeji birds and keep a ratio of 10 hens to one cock. That means that the eggs are fertile and if you incubate them, they will hatch into chicks after 21 days.

On my farm, I have a policy of disposing eggs laid earlier, what is called ‘first-in, first-out” principle in stock-taking language.

That is, I first ensure that all eggs have a date of lay and are arranged in that order. That way, I am able to sell eggs laid the previous week before selling those laid the next week.

I also ensure customers have a grace period of about 30 days after buying eggs during which they should have been consumed.

The exception is eggs sold to farmers for incubating, which must be between seven and 10 days old.

The eggs I sold Jackie were barely a month old and had been cleaned with warm water to remove dirt.


Now, to study the shelf-life of eggs, I decided to visit a few supermarkets to sample the average sell-by date and conditions under which they are kept before they are sold.

I learnt that on average, the shelf-life for most is about 30 days, plus 10 to 15 days. I would assume that this also depends on how long it takes from the time the egg is laid to the time it reaches the supermarket shelves.

One attendant told me this, “Generally, farmers have 30 days from the day an egg is laid to get it to stores. Then, the stores have another 30 days to sell the eggs. However, farmers are advised to ensure eggs reach retailers one-to-two days after being laid or within 72 hours”.

Another thing I observed was that in most supermarkets, eggs were stored at room temperature and not under refrigeration.

I also learned during my inquiries how eggs destined for supermarkets should be cleaned to remove dirt and if this affects how long they remain fresh.

One expert I spoke to told me, “Dirt on eggs may imply contact with chicken manure, which is a vehicle for transmitting salmonella.”

The problem is that washing an egg in water destroys the liquid coating called ‘cuticle’ or ‘bloom’ that is produced by the hen and which protects against aging, and attack by bacteria.

I was relieved when she said that the shelf-life of an egg has nothing to do with whether it is fertilised or unfertilised, but noted that the cleaning was perhaps the mistake my worker did.


The practice of “cleaning and sanitising” or “not cleaning eggs at all”, varies from place to place. In Europe, they say “don’t clean”, In America, they say “clean”.

She cautioned, “Careless washing procedures in water removes the cuticle and destroys the ‘natural protection’.

She advised that I practice good husbandry that ensures faecal matter from chicken doesn’t get into contact with the eggs in the first place.

In addition, she said that in the unlikely event that an egg needs cleaning, warm water is preferred to cold, since the latter contracts the eggs drawing in the dirty water that may contain the lethal bacteria through the invisible tens of thousands of pores found on the egg shell.

Salmonella is known to cause food poisoning in humans.

For now, I have embarked on my own egg preserving experiments and will be sharing results soon.

I plan to clean one set of eggs in warm water, another in cold water and a third will not be touched.

I will keep the eggs and observe which set stays fresh longer.

I will be looking out for smell, test and texture.

Look out for the results soon because I need to find out why my eggs went bad.

Obwogo is a medical doctor and a senior quality improvement adviser in health policy and systems strengthening at an international NGO.


Your Questions Answered

David Peter Okello, Busia: Kindly advise on marketing outlets for guinea fowls and turkeys and prices.

Unlike guinea fowls that are mainly marketed for ornamental purposes, there is high demand for turkey meat especially around Christmas season.

A pair of guinea fowl goes for Sh6,000 while a mature turkey goes for about Sh5,000.

You can get market via social media.

Nchalika: My Kari Improved Kienyeji hens started laying eggs at five months but I observed a 50 per cent reduction in production after changing to Kienyeji mash. From 16 hens, I was collecting six eggs and now only three daily.
First, I am not sure what feeds you were using before changing to the new brand.

Second, I think your hens are too few to conclude that the feeds may be the reason for reduced production.

Third, at five months, the hens are just starting to lay eggs and you should expect a peak after seven months.

Malachy Kipkeu: Kindly send me a handout on housing plans, vaccination schedule and disease control.
Please send me an email for a free copy.

Esther Wairimu Kiai:I have 300 layer chicks and would like to make my own feeds to cut costs. Advise on the ingredients required for chicks, growers and layers mash.
Making feeds is both a science and an art.

Please refer to my Seeds of Gold article of August 15 last year. I also offer hands-on training on formulating poultry feeds.

James Namasaka: How much capital do I need to start a poultry farm?
This will depend on the scale of production ranging from small (below 1,000 birds), medium (1,000-5,000) and large-scale (above 10,000 birds).

You also need to consider fixed (housing, feeders and drinkers) and running costs (labour, water, feeds and saw dust) of which feeds account for 60 to 70 per cent of the cost of producing eggs or meat.