They're a-laying Easter eggs, oddly from the bottom (5)
I believe the answer is:
geese
'they're a-laying' is the definition.
The definition suggests an adverb but the answer is not.
'easter eggs oddly from the bottom' is the wordplay.
'oddly' means one should take alternating letters (letters in odd-numbered positions).
'from the bottom' is a reversal indicator (in a down clue, letters come from the bottom).
'easter'+'eggs'='eastereggs'
The alternate letters of 'eastereggs' are 'eseeg'.
'eseeg' backwards is 'GEESE'.
Can you help me to learn more?
(Other definitions for geese that I've seen before include "Edible water birds" , "Large water-birds with webbed feet and broad bills" , "Stupid people" , "Birds; silly people" , "0 Water birds" .)