You might have too high salt concentrations in your samples. Try diluting them with deionized RNase free water.

A few comments here: 

A. When you have RNA degradation, the first peak that starts to disappear is that of 28S. By merely eyeballing your attached figure, it is evident that some of the lanes do show degradation - as evidenced by multiple bands. 

B. For a better understanding it would be better to label the ladder or better still - provide the electropherogram. You can take a look at the shape of the base line (flat or jagged) as well as the presence/absence of multiple peaks on the graph.

It depends on the organism you study and if you have denature your samples at 70°C during 2min before doing the RNA chip.

For example, if you work with RNA which are coming from some insects, the 28S pic disappear after denaturation... Even if they are eukaryotic organisms, the profiles of yeast will be different of mammalian cells, plants, insects...

Thank you all for answering! 

As Trouilh mentioned, I think the main reason is the optional denaturation. Look at this paper: Why does insect RNA look degraded? http://jinsectscience.oxfordjournals.org/content/10/1/159

"... the 28S rRNA of most insects contains an endogenous “hidden break.” Upon denaturation, the masking hydrogen bonds are disrupted, releasing two similar sized fragments that both migrate closely with 18S rRNA. The resulting rRNA profile thus reflects the endogenous composition of insect rRNA and should not be misinterpreted as degradation."

Dear Scientists,

Can somebody explain why the 5th sample from left has too many aligned faded bands? Was it a problem with sample or technical procedure?

Because if the RNA was degraded we would not have had such aligned bands, then we expected a smear like tape result.

Thank you.