‘Clown’ does not always mean a jester-type character, it can also and more prevalent in historical texts, mean (per the
OED):
A countryman, rustic, or peasant
eg
1849 Macaulay Hist. Eng. I. 610 ‘The Somersetshire clowns, with their scythes..faced the royal horse like old soldiers.’
As Leicestershire is the home of the pork pie, I would assume that the county was a byword for pork production and consumption.
The Guardian newspaper in 1821 published a letter, from which an extract follows, originally from the Durham Chronicle:
Extract of a letter from a Scotsman, just arrived in Manchester, to a friend in Auchtermuchty:
“Oh, man, but thae English loons are keen o’ eatin’! In our mither
kintra, a chiel wad think muckle shame to hae’t kent he made a god o’
his wame; but here awa folk crack aboot their flesh an’ blades, an’
their joints, an’ their puddins, an’ their pastry, as if it were nae
disgrace to a man to be sae muckle ta’en up aboot what he’s to eat and
what he’s to drink. Wi’ us, in Scotland, it’s aye left to the feckless
woman bodies to mak provision o’ necessars; but here, believe me ’gin
ye like, but I gie my word for’t, ye’ll see a muckle fat fallow gaun
to the merkat to buy meat; na, the vera men milk the kye! Heard ye
ever sicklike occupations for men?
They hae a kin o’ a provost here, wi twa kin o’ baillies; an’ what
think ye they’ve done. Kennin’ weel how weel John Bull likes guid
eatin, they hae coft a score o’ stots and threescore wathers, to kill
on the day Geordie has the gowden thing wi’ chuckystanes on’t putten
on his pow; an’ they hae sent them a’ roun the town wi’ ribbans at
their lugs. A stot wi’ a ribban at his lugs! An’ the pock puddins hae
been rinnin in hunners, every loon amang them settlin’ i’ his ain mind
the very collop he is to hae.
I've translated it for you ;-)
‘Oh man, but those English blokes are keen on their eating! In our mother country, a fellow would think great shame to have it known he made a god of his guts; but hereabouts folk talk about their meat and veg, their joints and their puddings and their pastry as if it were no disgrace to a man to be so much occupied about what he’s to eat and what he’s to drink. With us, in Scotland, it’s always left to the feeble female types to make provision of necessities; but here, believe me if you like, but I give you my word for it, you’ll see a big fat fellow going to the market to buy meat; indeed, the very men milk the cows! Did you ever hear of such work for men?
They have a kind of Mayor here, with two aldermen of sorts; and what
do you think they’ve done? Knowing how well John Bull likes good grub,
they’ve bought twenty bullocks and sixty lamb, to kill on the day
George IV has the golden thing with pebbles on it put on his head, and
they have sent them round the town with ribbons at their ears. A
bullock with a ribbon on his ears! And the Englishmen* have been
running in their hundreds, every man among them settling in his own
mind the very slab of meat he is to have.
** 'Pock-puddin' literally means a steamed pudding of the sort that is wrapped in a cloth. It was also used by Scots to describe Englishmen, in the same way the French might say Rosbifs.
pock-pud(ding), (i) a dumpling or steamed pudding cooked in a bag of muslin or similar thin material (Rxb. 1802 J. Sibbald Chron. Sc. Poetry Gl.; Sc. 1825 Jam.; wm.Sc. 1966). Also used attrib., = paunchy, gluttonous, as in 1705, 1827 and 1880 quots. Hence (ii) a jocular or pejorative nickname for an Englishman from the supposed fondness of the English for steamed puddings, with an additional implication of omnivorousness and stolidity
This letter is written just six years before Scott published 'Chronicles of the Canongate'and with its several references to Englishmen being inordinately fond of eating, meat especially, compared to Scotsmen, I think it supports an interpretation that this is about national stereotypes rather than wandering entertainers.
I would understand ‘Lei’cestershire clowns bolting bacon’ to be stereotypical meat-greedy Englishmen of a status not expected to be encumbered by social niceties of helping children and old men and able to just get on with the business of eating.