Several managers have mentioned that cellulitis was more prominent in high yield, slow feathering birds than fast feathering breeds. Averaging 10 days faster feather cover, the fast feather broiler quickly envelops their body in a coating of protection of feathers during the critical times of increased growth rate and activity. Delayed feathering simply allows more time for the skin to be exposed to trauma leading to scratches to the skin. Careful examination of any flock will reveal that there is a significant variation in feather coverage, ranging from birds with no feather coverage in the abdominal and tail regions to birds which are fully feathered.

Breed of the bird can also affect temperament or nervousness in a flock. Nervous flocks will be more active increasing the number or incidence of scratches and skin injuries (tearing). This is prominent in the white leghorn breeds versus the heavier boiler breeds.

Breed Sex
Males can be slower feathering allowing more skin injuries. However, pullets are known  to have more tender skin; hence, prone to more scratches or skin trauma.

Calorie / Protein ratio
If the ratio is too high (more energy) it could lead to lower intake of some essential amino acids. It could also lead to a higher deposition of abdominal fat. Deficient amino acids  could lead to feathering abnormalities and increased energy or fat deposition could cause skin integrity issues leading to skin fragility.

Amino acids, especially low or marginal levels of cysteine and methonine (sulfur groups) may cause nervousness and slow feathering. If amino acids levels are affecting feathering, the greatest effect probably starts during the first three weeks of the flock’s life (starter feed).

Nutritional
Other nutritional entities are sometimes implicated as contributing factors. Low sodium levels may contribute to increased nervousness in a flock. Vitamin E, the B vitamins and some trace minerals such as selenium and calcium have also been suspected of contributing to the problem

Feed Additives
For years it has been speculated that the side effects of antibiotics, anticoccidials and other feed additives have been associated with fragility of the skin. Recently a documented study  from Israel revealed that the skin of broilers fed halofuginone had less tensile strength, which could be associated with the increased frequency of skin tears and the incidence of scratches.

Density
Simply stated, too many birds per square meter can impact both feathering and scratches. Reduced bird densitycan often reduce skin damage. Is this contributing factor significant  in the correlation to skin scratches therefore cellulitis is questioned. Morris 1999 revealed  that there was no pattern between levels of cellulitis in a complex and the size of the bird raised or the stocking density. Norton however, reveals that birds under higher density  will tend to have more scratches and therefore higher rates of cellulitis. Management of density should always be conducted on the basis of kilos/meter2 rather than birds/meter2. The key is "manage density rather density manage you."

One cannot deny that skin scratches may be artificially created by high bird density by  farm management. During hot weather birds may crowd to one end of a house trying to  seek the ventilated cooler areas (tunnel ventilation). Partial brooding may encourage birds to remain in the brooding area. No doubt designing the house, locating the equipment and managing the flock to keep the birds spread out can and will reduce skin scratch challenges.