2.2 Layer Pullets - T2

Question 1

Are white egg layers or brown egg layers smaller?

Answer 1

White egg layers tend to be smaller birds

Question 2

Do most primary breeders sell white or brown egg layers?

Answer 2

Most primary breeders sell both white and brown egg layers
*feather colour does not equal egg colour

Question 3

What is the goal of pullet rearing?

Answer 3

Prepare birds for egg production
- body weight and composition (to maintain high levels of egg production)
- nutrient reserves

Question 3

What are the 4 phases of the laying hen production cycle? What do exact ages depend on?

Answer 3

1. Pullet rearing: 0 to ~15wks
2. Pre-lay: ~16 to ~18wks
   - move pullets to layer barn
   - photostimulate
3. Laying: ~18 to ~70wks
4. Depopulation: ~70wks

Exact ages depend on:
- strain, management (early in life)
- market forces, shell quality (late in life)

Question 3

What are the goals during sexual maturity to peak daily egg mass in layer feeding programs?

Answer 3

1. produce large numbers of eggs
   - rapid increase in egg size
2. produce Large eggs
3. feed intake may be limiting
   - nutrient reserves may be decreased during this stage

Question 4

What are the goals from peak egg mass to end of production in layer feeding programs?

Answer 4

1. maintain high numbers of eggs
2. prevent eggs from becoming too large
   - larger eggs require greater nutrient mobilization per egg

Question 5

What is the ‘motto’ with pullet feeding?

Answer 5

Start with the end in mind
- aka what are we going to ask the bird to do in the barn

Question 6

Longer laying cycles means…

Answer 6

Greater persistency
- production is higher in general
- persistency = able to produce eggs to an older age

*for birds to handle this production, have to prepare the pullet

Question 7

Before sexual maturity, what do we want to achieve with birds? Why?

Answer 7

Need appropriate body weight/size/composition before sexual maturity
- larger early eggs
- nutrient reserves
- less prone to subsequent problems (ex. rapid drop in production following peak, osteoporosis)

Question 8

What happens if pullets receive insufficient energy prior to peak production?

Answer 8

Too small appetite/body weight
- will reach peak production then go WHOA I’m losing too much body protein and fat and take a break; limited nutrient reserves they can put towards production, so they slow down rate of egg production
- will replenish reserves and production line will come up but egg production is not ever as high

Question 9

Each bird has unique nutrient requirements, but how do we feed a flock?

Answer 9

On a flock basis
- flock uniformity is important
- if there isn’t uniformity, some birds will be receiving too much, others too little
- when a flock is uniform % production will better reflect % lay and there will be good persistency
- uneven flock; take longer to come into production and peak egg production isn’t as high

Question 10

How should the management guide for feeding programs be viewed?

Answer 10

It is a guide, not a rulebook or calendar
- feed and manage the birds according to their needs, not a schedule

Question 11

In a pullet feeding program, there isn’t a crude protein “requirement”, rather birds require what?

Answer 11

CP is a guideline for practical diets, birds have a requirement for:
1. essential amino acids
2. amino nitrogen supply

Question 12

What happens from ~15-18 wks?

Answer 12

Pullet is growing
1. Body weight
- constant % protein
- increasing % fat (important in terms of providing the lipid to form an egg yolk)

2. Bone mineral reserves
   - minimal increases in bone length
   - Increases in bone DIAMETER = development of medullary bone and increase in body ash
3. Entering sexual maturity
   - body composition
   - development/growth of reproductive tract
   - no new deposition of cortical bone
4. Setting the stage for the rest of the production cycle
   - deposition of medullary bone

Question 13

From 15-18 wk, deposition of medullary bone begins. What happens?

Answer 13

• Bone diameter increases by ~20%
• Medullary bone deposited ~10-14d before 1st egg
• Continues as long as the hen is in lay

Question 14

How can feeding for body weight/condition be achieved?

Answer 14

1. Stimulate feed intake
   - Feed small amounts, often
   - Midnight feeding in hot climates
2. Prepare pullets for increased feed intake at lay
   - Higher fiber diets to increase capacity to consume more feed
3. Coarse fiber feeding
   - Stimulate gizzard size, development
   - Gut microflora
   - Litter quality
   - Welfare
4. Weigh pullets and make feeding decisions accordingly
5. Target body weight
   - Egg size; economics and shell quality

Question 15

Is it difficult to change the body weight trajectory in lay?

Answer 15

YES! That is why pullet nutrition is so important

Question 16

What is meant by “a quality pullet is not just about the right weight at transfer”?

Answer 16

If a bird is underweight for awhile and a decision is made to increase BW but this is made too late physiologically. So the bird starts depositing more fat. Same body weight as the other birds at the end, but the body comp is completely different.

KEY: weight birds regularly early on so more subtle changes to feed can be made; SUBTLE FREQUENT CHANGES ARE BETTER

Question 17

Diet changes should be made based on what?

Answer 17

Make diet changes based on bird requirements, not age
- can delay the switch to next diet phase
- can delay photostimulation (since laying hens are still seasonal breeders); increasing daylength initiates sexual maturity

Question 18

Layers are long lived birds so we tend to vaccinate them more than broilers, beginning with pullets. What happens after vaccination?

Answer 18

After a vaccination we stimulate an inflammatory response and often see a drop in the rate of gain
- With the 1st vaccine this is taking place when GI and muscle still is developing so when they lose that rate of gain we have to try and catch them up
- Catch them up by switching by to an earlier phase diet

Question 19

Are layer pullets prone to being overweight?

Answer 19

Generally not, but it can happen

Question 20

What is a negative signal for reproduction (egg laying)?

Answer 20

Trying to limit growth as sexual maturity approaches
- limit growth as a way of correcting overwt birds, but this is not the way to do it bc it results in poor uniformity and some will stop developing sexually
- instead re-draw the growth curve parallel to original (but higher)
- best action would have been to monitor the birds when they were younger

Question 21

When are pre-lay diets sometimes used?

Answer 21

Mature body weight to ~5% production
- bird should already be at mature body size; very little nutrients needed for body growth; nutrients to support bones, oviduct, follicle development
- increase in Ca for medullary bone deposit

Question 22

Why should pre-lay diets be used with extreme caution? Why is managing a pre-lay diet difficult?

Answer 22

• Short feeding time (no more than 10 days)
• Too little calcium to support egg production
• Commercial farm feed management: order amount of feed needed, next batch is put in the bin ON TOP of the previous batch; not a removal of old feed/replacement